• Mix all purpose flour and active dry yeast. In a bowl mix milk, salt, sugar and egg, before adding half the flour. Mix in the butter, before you add the rest of the flour.
• Knead the dough for about five minutes. The dough will be sticky and very soft. Do not add more flour! You don’t want a dry base, and you won’t have to touch the dough much after the first rise.
• Cover your bowl with a plastic bag and leave your dough to rise for 45 minutes in a warm spot.

Make the vanilla custard

• Heat the milk to the boil in a small sauce pan. Whisk the egg yolk with vanilla, sugar and corn starch, until it is light and fluffy.
• Pour in the hot milk, while still whisking. Pour the custard back into the sauce pan, put it over low heat and keep whisking, until it thickens. It must not boil or burn, just keep whisking.
• Pour the custard into a small bowl, cover it with plastic wrap and leave to cool in the fridge.
• Cover a baking pan (10×14 inches) with baking paper. (If you soak the paper in water, it will be easier to make the paper stick to the pan, also in the corners.)
• Carefully tip the dough into the baking pan, and scrape down the sides of the bowl. Stretch the dough to the corners of the pan. Soak your fingertips in water, so the dough won’t stick. Do not press the dough too much. You don’t want to let out too much air;-) Cover the dough again and leave it to rise for 20 minutes.
• Meanwhile, heat the oven to 410° F.

While the dough rises, make the sugar topping

• Mix margarine and packed brown sugar in a sauce pan, and stir it over medium heat, until the margarine melts. Remove from the heat and whisk in the vanilla custard, until smooth and set it aside.
• When your cake base has risen, make small indentations with your fingertips all over the cake. Do not make them too deep, just small ‘dimples’. Cover the base with 2/3 of the topping. The topping must cover the edges, but must not run down the sides of your brunsviger.
• Bake your brunsviger for 16-18 minutes. When you remove the cake from the oven, cover your cake with the rest of the topping and leave it to cool.
• Your brunsviger will be best, when it is freshly baked, and the sugar topping runs down your fingers:-)