Gateau Breton

Directions

1. 1
   Preheat the oven to 375 degrees F (190 degrees C). Grease a 9-inch springform pan.
2. 2
   Mix 1 teaspoon egg yolk and water in a small bowl. Set aside for glazing the cake.
3. 3
   Combine remaining egg yolks, flour, butter, sugar, and cornstarch in a large bowl. Mix with an electric mixer until dough is stiff and sticky, similar to cookie dough. Knead dough a little bit to bring it together.
4. 4
   Press dough into the prepared pan with your hands. Brush glaze on top.
5. 5
   Bake in the preheated oven for 15 minutes. Reduce temperature to 350 degrees F (175 degrees C). Continue baking until golden brown, about 25 minutes more. Cool for 10 minutes. Slice cake crosswise.