Step 1

Preheat the oven to 200 degC

Step 2

Remove the stalk of the tomatoes, and slice.

Step 3

Roll out 2/3 of the pastry into a square with a thickness of several millimeters. It should be about 35 cm square.

Step 4

Roll out the other 1/3 into a 20cm square, and cut into strips.

Step 5

Smear the butter around the inside of a 20cm square baking dish.

Step 6

Lay the 35 cm square piece of pastry into the baking dish. It is OK if it extends above the edges, as it will shrink a bit.

Step 7

Bake in the oven until it starts getting a little crisp and puffing up.

Step 8

Remove from the oven.

Step 9

Lay half the prosciutto on top of the pastry.

Step 10

Lay half the sliced tomatoes on top of the prosciutto.

Step 11

Break 4 of the eggs on top of the tomatoes.

Step 12

Sprinkle half the green onions over the eggs.

Step 13

Repeat with the other half of each of these ingredients.

Step 14

Top with the strips of pastry in a pattern of your choosing.

Step 15

Brush with the whisked egg yolk.

Step 16

Bake in the oven for 30 to 45 minutes, until the pastry crisp and golden.

Step 17

Rest for 10 minutes before cutting and serving.