I went wild over this cake when I tasted it for the first time at Bell’s, a French bistro in Los Alamos, California. Its butteriness and shortbread-like texture are what made me an instant fan. How can a cake with only four ingredients be so good? It’s the quality of the butter you use. Common supermarket brands are 80% butterfat, the lowest allowed by the USDA. But if you seek out brands such as Kerrygold, Plugra, Strauss, or Horizon, their butterfats range from 82% to 85%. Remember, fat carries flavor!
This cake is amazingly easy to make by hand, with an electric mixer, or in a food processor. Egg yolks hold the batter together. An egg yolk glaze, raked with the tines of a fork, give the cake a decoration and a beautiful burnished look.
This butter cake from Brittany is easy to make with a food processor, an electric mixer, or completely by hand. I’ve written complete directions for all three methods. If using unsalted butter instead of salted, add 1/2 teaspoon salt to the dry ingredients. You’ll need an 8 x 2-inch round metal pan. If you have an 8-inch layer cake pan it will work perfectly. The vanilla in the recipe is my addition.
2 cups all-purpose flour (spooned into a 1-cup dry measure to overflowing and leveled with a straight edge; 9 ounces by weight)
8 ounces (2 sticks) salted or unsalted butter, refrigerator temp or slightly softened, depending on method
1 cup sugar
6 large egg yolks
1 teaspoon pure vanilla extract or 1/2 teaspoon vanilla paste
1. Adjust an oven rack to the center position and preheat the oven to 350 degrees. Butter the cake pan and line the bottom with a round of cooking parchment or waxed paper. No need to butter the paper.
2. To make the dough in a food processor, put the flour and sugar into the work bowl. Process 5 seconds to combine. Cut the cold butter into 1/2-inch cubes and add to the work bowl. Pulse about 5 times for 1 second each to cut the butter into small pieces no larger than 1/4-inch or so. Add 5 egg yolks and the vanilla and pulse rapidly 10 to 15 times (more or less) until a stiff dough comes together. Remove the dough from the machine and work it briefly between your hands to form a thick disk. If the dough sticks at all, flour your hands very lightly. Put the dough into the prepared pan and set a piece of plastic wrap over it. Press on the plastic to spread the dough into the pan. It should be evenly thick and reach right to the pan edge. Refrigerate about 20 minutes.
3. If using an electric mixer, cut the slightly softened butter into tablespoon-size pieces and put them into a medium bowl with the sugar. Beat for 2 to 3 minutes on medium speed until well mixed but not fluffy. Add 5 egg yolks and the vanilla and beat on medium speed about 1 minute, until completely incorporated. With a wooden spoon, gradually stir in the flour to make a stiff dough. Scrape the dough into the prepared pan and set a piece of plastic wrap over it. Press on the plastic to spread the dough into the pan. It should be evenly thick and reach right to the pan edge. Refrigerate about 20 minutes.
4.To make Gâteau Breton by hand, put the flour and sugar into a large mixing bowl and stir to mix. Cut the cold butter into 1/2-inch cubes and add to the bowl. Chop the butter into the flour and sugar with a pastry blender or two knives until the texture is like coarse crumbs. Add 5 egg yolks and the vanilla and mix in with a wooden spoon to form a thick dough. Put the dough into the prepared pan and set a piece of plastic wrap over it. Press on the plastic to spread the dough into the pan. It should be evenly thick and reach right to the pan edge. Refrigerate about 20 minutes.
5. To bake the Gâteau Breton, mix the last yolk and 1 teaspoon water in a small cup well with a fork. Remove the plastic wrap from the chilled cake and use a pastry brush to coat the top of the cake with the egg yolk. You may not have to use all the yolk. Try not to let any yolk run between the cake and the side of the pan. With a table fork, score the top of the Gâteau Breton in criss-crossing parallel lines.
6. Bake for 45 to 50 minutes, until the cake is a rich golden brown color. Cool the cake on a wire rack for 10 minutes. Run a small knife around the sides of the Gâteau to release, and unmold it onto the rack. Peel off the paper, cover with another rack, and invert to cool right side up. Wait a few hours before serving for the cake’s texture to compose itself.
Makes one 8-inch round cake, about 10 servings.