Key Lime Pie

Ingredients

• 250 gDigestive biscuits
• 100 gGingernut biscuits
• 150 g, meltedButter or baking spread
• 3Egg yolks
• 397 gCondensed milk
• 4Limes, zest and juice
• 300 mlDouble cream
• 1 tbspIcing sugar
• 1 tspVanilla extract
• To taste, optionalLime zest

Instructions

1. 1

   Heat the oven

   Preheat the oven to 160°C fan/180°C (350°F/Gas Mark 4).

2. 2

   Crush the biscuits

   Whizz the Digestive and Gingernut biscuits into crumbs in a food processor. Alternatively, put them in a bowl and crush them with a rolling pin.

3. 3

   Make the base

   Stir the melted butter into the biscuit crumbs, then press the mixture into a 23 cm loose-bottomed tart tin.

4. 4

   Bake the base

   Bake the base for 10 minutes, then remove it from the oven and leave it to cool.

5. 5

   Whisk the yolks

   Beat the egg yolks with an electric mixer for a few minutes.

6. 6

   Add condensed milk

   Whisk the condensed milk into the beaten yolks.

7. 7

   Flavour the filling

   Add the lime juice and zest, then whisk the mixture for a few minutes.

8. 8

   Bake the filling

   Pour the filling into the biscuit base and bake for 15 minutes, or until set but still slightly wobbly. Leave the pie to cool completely.

9. 9

   Whip the cream

   Whip the cream with the icing sugar and vanilla. Pipe or spoon it over the cooled pie, then scatter over lime zest.

10. 10

    Serve the pie

    Serve immediately and keep any leftovers in the fridge for 2–3 days.

What is key lime pie?

Key lime pie is an American dessert known for its sharp citrus filling, creamy texture and biscuit base. This version uses ordinary limes and a mixture of Digestive and Gingernut biscuits for a buttery base with a gentle spice note.

Condensed milk gives the filling its characteristic richness, while lime juice and zest bring the tang. A topping of whipped cream softens the citrus and completes each slice.

Nutrition and macros by portion

The nutrition label shows one serving as written: 437 calories, 6g protein, 43g carbs, 28g fat.

The biscuit base contributes most of the carbohydrates, while butter, condensed milk and double cream account for much of the fat. Egg yolks and dairy provide some protein. Balance a slice with fresh fruit, or serve it after a lighter main course.

Why use two biscuits?

Digestives: these make up the main body of the base and have a mild, wheaty flavour.

Gingernuts: their spiced biscuit flavour adds contrast to the lime without taking over. Crush both types finely so the butter can bind the crumbs evenly.

Getting the base right

Even crumbs: use a food processor or crush the biscuits in a bowl with a rolling pin. Aim for an even, fine texture so the base holds together when sliced.

Firm press: spread the buttered crumbs across the base and up the sides of the tin, pressing them into a compact layer. The 10-minute bake helps the base set before the filling goes in.

A smooth lime filling

Egg yolks: whisk them for a few minutes before adding the condensed milk, as directed. This helps create an even mixture.

Lime: zest the fruit before juicing it, then whisk both into the filling. The zest gives the pie a fresh citrus aroma alongside the juice's tang.

How to judge doneness

Look for a filling that has set around the edges but still has a slight wobble in the centre after 15 minutes. It will continue to settle as it cools, so avoid waiting for the centre to become completely firm in the oven.

Cool the pie completely before adding the cream. This gives the filling time to settle and helps the topping stay in place.

Cream and serving

Whip the double cream with the icing sugar and vanilla until it can be piped or spooned over the pie. Add the optional lime zest just before serving for a fresh finish.

The pie is rich and tangy, so small slices work well after a meal. Fresh fruit alongside is a simple way to add a fresh contrast.

Recipe notes & tips

• Zest the limes before cutting and juicing them.
• Crush the biscuits evenly so the base presses into a cohesive layer.
• Use the base-baking time to prepare the filling ingredients.
• Watch for a slight wobble in the middle rather than waiting for the filling to look completely firm.
• Let the pie cool completely before piping or spooning on the cream.

Variations

• More lime: Add extra lime zest to the cream for a brighter citrus finish.
• Plain biscuit base: Use Digestive biscuits in place of the Gingernuts for a milder base.
• Ginger finish: Sprinkle a little crushed Gingernut over the cream for extra spice and crunch.
• Individual portions: Divide the biscuit base and filling between smaller tart tins, checking for doneness as they bake.
• Unadorned slices: Serve the pie without whipped cream for a sharper, less creamy finish.

Common mistakes to avoid

• Coarse biscuit crumbs: Crush them more finely so the base binds and slices cleanly.
• Loose base: Press the crumbs firmly into the tin before baking.
• Overbaking the filling: Take it out when the centre still wobbles slightly.
• Topping a warm pie: Cool it completely first so the whipped cream holds its shape.
• Skipping the zest: Zest the limes as well as juicing them to bring their fragrant citrus flavour into the filling.

How to store

Cover and keep leftover pie in the fridge for 2–3 days. Serve chilled; the recipe does not specify reheating.

Frequently asked questions