Step 1

Thaw the puff pastry.

Step 2

Cut the vanilla bean in half lengthwise and scrape out the seeds. Pour the milk into a saucepan, stir in the flour, vanilla, salt and butter and bring to a boil while stirring once. Remove from the heat, stir in the cornstarch and let cool slightly.

Step 3

Separate the eggs. Beat the egg whites until stiff, gradually adding the sugar. Mix the egg yolks with the warm semolina mixture and gently fold in the egg whites.

Step 4

Roll out the puff pastry and line the buttered ramekins with it.

Step 5

Spread the semolina mixture in the ramekins and bake on the lower rack in an oven preheated 200°C (approximately 400°F) about 30-40 minutes until golden brown.

Step 6

Meanwhile peel grapefruits, remove the white pith and section the fruit.

Step 7

Remove the tarts from the oven, top with grapefruit, dust with powdered sugar and serve immediately.