Instructions
Preheat your oven to 160°C (fan 140°C, gas mark 3) to prepare for baking the biscuit base. Using a food processor, blitz the digestive biscuits until they become fine crumbs. If you don’t have a processor, place the biscuits in a sturdy plastic bag and crush them thoroughly with a rolling pin until finely ground. This ensures a smooth, even crust. Combine the biscuit crumbs with the melted butter, stirring until every crumb is coated and the mixture resembles wet sand. Press this mixture firmly into the base and up the sides of a 22cm loose-based tart tin, creating an even crust about half an inch thick. Bake the crust in the oven for 10 minutes to set it and deepen the buttery flavor. Once baked, remove from the oven and let it cool completely to ensure it remains crisp when the filling is added. In a large bowl, place the egg yolks and whisk using electric beaters for about one minute until slightly thickened and pale. Gradually add the condensed milk, continuing to whisk vigorously for 3 minutes to incorporate air and achieve a silky mix. Stir in the freshly grated zest and juice of the limes, then whisk again for another 3 minutes. This step infuses the filling with vibrant citrus flavor and helps it thicken. Pour the luscious filling into the cooled biscuit base, smoothing the top with a spatula. Return the pie to the oven and bake for 15 minutes. The filling should be set but still slightly wobbly in the center, as it will firm up when chilled. Remove the pie from the oven and let it cool at room temperature before transferring it to the refrigerator. Chill for at least 3 hours, preferably overnight, to allow the flavors to meld and the filling to fully set. When you’re ready to serve, carefully release the pie from its tin and place it on a serving plate. In a chilled bowl, softly whip the double cream with the icing sugar until it forms gentle peaks. Dollop or pipe the whipped cream over the top of the pie, adding an elegant touch. Finish by sprinkling extra lime zest over the cream for a zesty aroma and pretty garnish. Tip: Ensure the pie is thoroughly chilled for clean slices, and use finely grated lime zest to avoid any bitter white pith. For an extra touch, serve with fresh lime slices or a scattering of fresh berries.
