A tangy lime filling in a crunchy, buttery cookie-crumb crust topped with a mound of creamy toasted meringue. All you need are a few simple ingredients and half an hour of your time, and you can be tucking into this Key Lime Pie tonight.
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What is key lime pie?
A key lime pie is an American dessert with a tangy lime filling in a buttery cookie-crumb crust. It can be topped with either meringue or whipped cream, or served plain with a spoonful of whipped cream on the side. It is very similar to an English lemon meringue pie.
Authentic key lime pie is made with limes which are grown in the Florida keys. These limes are highly prized for their intense citrus flavour, and they also have a thinner rind than the Persian limes we get in the UK.
If you can’t get hold of key limes, you can substitute them with normal limes (as I have done here), and while the pie will still be delicious, it won’t have the intense lime flavour that you would get by using key limes.
Ingredients for a key lime pie
To make a key lime pie, you need surprisingly few ingredients. You can get the exact quantities and full instructions on the printable recipe card at the end of this post.
Cookies or biscuits – These are used to make the pie crust, and should be pulverised into crumbs. I like to use Nice biscuits as they are sweet enough not to have to add any sugar. If you live in the US and decide to use Graham crackers for the crust then I would suggest adding 2 tablespoons of sugar to the crumb mixture.
Butter – This is mixed with the cookie crumbs to help hold the together.
Limes – You will need both the juice and the zest from the limes. You can zest the limes before squeezing the juice out, by running then over the smallest holes on a cheese grater, or by using a citrus zester. To get the most juice from your limes you can either roll them under your hand on the counter top, or put them in the microwave (on full power) for about 10 seconds. The actual number of limes you will need depends on how juicy the limes are. You will need about 1/4 of a cup of juice.
Eggs – The eggs should be separated. The yolks will be used in the filling, and the whites will be used to make the meringue topping.
Condensed milk – This is used for the filling.
Sugar (not pictured above) – Used to sweeten the meringue mixture.
Cream of tartar (not pictured above) – This is used to stabilize the egg whites for the meringue.
How to make the key lime pie
You will need a 7″ (17cm) metal pie dish with a loose, removable bottom. This will make it much easier to get the finished pie out of the dish if you use one of these. You can also use an 8″ pie dish, but then the filling will not be quite as deep.
There are only a few simple steps to make this yummy pie.
- Make the pie crust and bake for 10 minutes
- Prepare the filling and bake for 10 minutes
- Whisk the meringue and brown for 5 minutes
Make the pie crust
- Crush the biscuits (cookies) to a fine crumb by placing them in a plastic bag and hitting them with a rolling pin. An easier way to do this is to just blitz them in a food processor. Get the crumbs as fine as possible. Transfer the crumbs into a mixing bowl (image 1 above)
- Melt the butter in the microwave, or in a saucepan on the stove and then pour into the crumbs. If you are using Graham cracker crumbs you can add 2 tablespoons of sugar at this stage.
- Mix the crumbs with a fork until they are completely coated with the butter and are slightly damp (image 2 above).
- Press firmly into your pie dish, taking care to compact them well, and press them evenly around the sides. I like to use a small bowl to help me get them nice and even (image 3 above).
- There is already a lot of butter in this crust, so it should not be necessary to grease the pie dish before forming the crust.
- Bake the pie crust in a preheated oven (175C / 350F) for 10 minutes. Remove from the oven and allow to cool.
Make the filling
- Wash the limes, then zest them. Take care only to zest the green part of the skin, don’t take any of the underlying white skin, which is inclined to be bitter. Cut the limes in half and squeeze the juice into a cup.
- Beat the egg yolks and condensed milk together in a small mixing bowl (image 1 above) and then add the lime zest and juice.
- It will initially look as though the mixture has curdled, but don’t worry – this is normal. Mix well and the mixture will thicken and become smooth (image 2 above)
- Pour the filling into the cooled crust (image 3 above).
- Bake the pie for 10 minutes, then remove from the oven and allow to cool.
Make the meringue and brown
Tip for beating egg whites – make sure your utensils are scrupulously clean with no specks of grease, and do not allow even the smallest particle of egg yolk mix with the whites or they will not stiffen, no matter how long you beat them.
- Whisk the egg whites with 1/2 teaspoon cream of tarter until they start to thicken and then add the sugar.
- Continue whisking until the sugar is completely dissolved and the egg whites are thick and glossy.
- You should be able to hold the bowl upside down without the egg white falling out.
- Spread the meringue on top of the cooled pie, taking care to cover the pie completely. Form peaks on the meringue with a spoon (image 4 above).
- Place the pie back in the oven for a final time and bake for 5 minutes until the meringue starts to brown.
- KEEP YOUR EYE ON IT. The meringue browns very quickly and can turn from perfect golden brown to almost burned in an instant.
- I found this out the hard way as literally turned my back for 2 minutes while I started the washing up as the pie was baking 🙂
- Remove from the oven and allow to cool, then store in the refrigerator until you are ready to eat it.
Luckily I got to it in time! And to prove it here’s a message sent to me from my friendly neighbour/recipe tester after I presented her with a slice to try:
I didn’t think the pie was burnt at all
Official recipe tester verdict
Crunchy base and light as a feather topping. Yum yum x
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Storage instructions
You should store this pie in the refrigerator, it is not suitable for freezing.
It will remain fresh in the refrigerator for 3 to 4 days, after that it will start to weep and become soggy.
Variations
Instead of topping your key lime pie with meringue and browning it in the oven, you could just top it with whipped cream instead. (This way you would not run the risk of burning it).
Don’t put any topping on it at all – just serve it plain, or with a spoonful of whipped cream on the side.
Instead of making a cookie-crumb crust, make a flaky pastry crust. See this post for coconut meringue jam tarts (hertzoggies) for a recipe for homemade flaky pastry.
Or why not just make the lime filling and spoon it into a wine glass between layers of whipped cream for an elegant dinner party dessert.
If you enjoyed this recipe for key lime pie you may like some of my other creamy dessert recipes too.
- Puff pastry custard slices with creme patissiere
- Creamy Eton mess with 1-minute meringues
- Fresh pear cream slice
- No bake pineapple icebox cake
- Boozy Black Forest trifle with cherries and cream
- Citrus cheesecake with Greek yoghurt
- Peppermint crisp fridge tart
Pin for later
Why not pin this recipe to your pinterest board so you can make it later. Just click the image below.
Key lime pie with creamy meringue topping recipe
Key lime pie with creamy meringue topping
(Click the stars to rate this recipe)
Equipment
- 7" loose-bottomed pie or flan dish
Ingredients
- 9 ounce (250g) Nice biscuits (cookies)
- 3 ounce (85g) butter melted
- ¼ cup freshly squeezed lime juice 3 to 4 limes
- 1 tablespoon lime zest
- 3 large eggs separated
- 14 ounce (397g) can condensed milk
- 3 tablespoons sugar
- ¼ teaspoon cream of tartar
Instructions
Make the pie crust
- Preheat the oven to 175°C/350°F
- Crush the biscuits into fine crumbs. *Notes 1 and 2
- Melt the butter in the microwave or in a saucepan on the stove and then pour into the biscuit crumbs and mix well to combine.
- Press the crumbs into the pie dish covering the base and sides evenly. *Note 3
- Place the pie dish in the oven and bake for 10 minutes.
- Remove from the oven and allow to cool.
Make the filling
- Wash the limes and remove about 1 tablespoon of zest. *Note 4
- Cut the limes in half and squeeze out ¼ cup of juice. *Note 5
- Beat the egg yolks and condensed milk together until combined then mix in the juice and zest from the limes. *Note 6
- Pour the filling into the cooled pie crust then return to the oven and bake for a further 10 minutes.
- Remove from the oven and allow to cool.
Make the meringue
- Whisk the egg whites with ½ teaspoon of cream of tartar until they start to thicken, then add the sugar. *Note 7
- Continue whisking until the sugar is completely dissolved and the egg whites are thick and glossy.
- Spread the meringue on top of the cooled pie, taking care to cover the pie completely.
- Return the pie to the oven for the final time and bake for approximately 5 minutes until the meringue starts to brown. *Note 8
- Remove from the oven and allow to cool. Store in the refrigerator and serve chilled.
Notes
- To crush the biscuits, place them in a plastic bag and hit them with a rolling pin. Alternatively, blitz them in a food processor. Get the crumbs as fine as possible.
- If you are using Graham crackers you may want to sweeten then by mixing 2 tablespoons of sugar into the crushed cookie crumbs.
- You may find that a small flat-bottomed bowl or dish will help to compact the crumbs evenly.
- To zest the limes, use the smallest holes on a cheese grater or use a lemon zester. Take care to only zest the coloured part of the skin – the underneath white layer will be bitter.
- The actual number of limes you will need depends on how much juice they contain. To get the maximum amount of juice from a lime, roll it on the counter-top or put it in the microwave on full power for 10 seconds.
- It may look as though the mixture has curdled when you add the lime juice, but just keep mixing until the mixture is thick and glossy.
- Make sure your bowl and whisk are completely clean and grease-free when whisking the egg whites. If not, there is a chance that the egg whites will not stiffen. The egg whites will be stiff enough when you can hold the bowl upside down without the egg whites falling out.
- When browning the meringue, keep your eye on it. It can turn from golden brown to burned in the blink of an eye.
Nutrition
I am not a nutritionist. The nutrition information has been calculated using an on-line calculator, and is intended for information and guidance purposes only. If the nutrition information is important to you, you should consider calculating it yourself, using your preferred tool.
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