Preheat the oven to 200°C (400°F/Gas 6). Place the coconut, sugar, butter and flour in a food processor and blitz until the mixture resembles breadcrumbs.
Remove roughly 180g (6½oz) of the mixture and set aside for the topping. Add the egg to the remaining pastry mixture along with the vanilla extract, if using, and blitz until the dough begins to clump together.
Press the dough into the base and sides of a 23cm (9in) tart tin, 2.5cm (1in) in depth and with a removable base, until you have a smooth surface. Place in the oven on the middle shelf to bake for 10–12 minutes.
Mix the strawberry jam with a spoon to loosen it. Remove the tart tin from the oven and spread the jam across the base. Use your fingertips to form little clumps of the reserved pastry mix, put these clumps on top of the tart and pop back in the oven to cook for 15 minutes until the topping is golden brown.
Remove from the oven and allow the tart to cool on a wire rack before removing from the tin and placing on a serving platter. Serve slices with freshly whipped cream or some good-quality vanilla ice cream.