Step 1

Place the flour into a large mixing bowl and add the cubed butter. Using your fingertips, rub the butter into the flour until the mixture resembles fine breadcrumbs.

Step 2

When no large lumps of butter remain, add 2-3 tablespoons cold water 1 teaspoon at a time and stir with a round-ended knife until the pastry starts to clump together. You may not need to add all the water, or you may need a little more. Knead the dough briefly to bring it together into a ball, then wrap in clingfilm and chill for at least 15 minutes.

Step 3

Preheat the oven to 180°C, gas mark 4. Roll the chilled pastry out on a lightly floured surface or between two pieces of clingfilm to 5mm thickness, then press it into a 23cm, deep tart tin. Roll the rolling pin across the top of the tin to cut off any excess pastry, then prick the base with a fork and chill for a further 15 minutes.

Step 4

Line the pastry case with a sheet of baking parchment and fill to the top with baking beans, dried rice or lentils. Bake for 15 minutes, then remove the baking beans and bake for a further 10 minutes until the base is crisp.

Step 5

To making the filling, pour the chilled evaporated milk into a large bowl or the bowl of a stand mixer and add the sugar. Whisk on high speed for 10-15 minutes until the mixture is light and fluffy and resembles softly whipped cream. The sugar grains should have dissolved completely.

Step 6

Reduce the oven temperature to 160°C, gas mark 3. Fill the tart case with the filling, leaving 1cm at the top for the filling to expand and sprinkle with sea salt. Bake the tart for 5 minutes, so a thin crust is just beginning to form on the top, then remove from the oven. It is important not to overbake the tart, as when the sugar gets too hot, the filling with liquefy rather than set. A few extra minutes in the oven is all that is needed to do this. The filling should be mousse-like and light.

Step 7

Allow the tart to cool to room temperature, then serve with a big dollop of crème fraîche or soured cream to cut through the intense sweetness.