Instructions

1. 1

   Preheat the oven to 180°C (350°F/Gas 4). Melt the butter in a saucepan over a low heat. Add the digestive biscuit crumbs and stir until well combined. Remove from the heat and tip the mixture into the flan tin, then use the base of a metal spoon to press it evenly and firmly all over the base and sides of the tin. Place on a baking tray and bake for 5–10 minutes.

   
   

2. 2

   Meanwhile, grate the zest of 3 of the limes into a bowl. Juice all 5 of the limes, and set aside.

   
   

3. 3

   Place the egg yolks into the bowl with the lime zest, and whisk until the egg has thickened. Pour in the condensed milk and continue whisking for 5 minutes if using an electric whisk, or for 6–7 minutes if whisking by hand. Add the lime juice, and whisk again until it is incorporated. Pour the mixture into the tin and bake for 15–20 minutes, or until it is set.

   
   

4. 4

   Remove the pie from the oven and leave it to cool completely. Serve the pie decorated with the lime slices.