This galette is a bit different from the standard galette made with a pastry crust. What sets this apart from the others is the crust is made from a buttermilk biscuit dough! With the sudden abundance of ripe tomatoes in the garden, this was the perfect recipe.
1 3/4 cups flour, plus more for dusting/rolling
2 teaspoons baking powder
1 teaspoon sugar
1/2 teaspoon salt
6 Tablespoons unsalted butter, cut into small slices
3/4 cup cold buttermilk (make sure to shake the carton well)
Semolino flour
Combine all the ingredients except for the buttermilk. Using the whisk attachment on your mixer or a pastry blender, cut the butter into the flour mixture until it resembles a course meal with pea size lumps of butter. Place bowl into the refrigerator. While chilling, prep the filling for the gallette. Then stir in the buttermilk using a spatula. Do not over mix. The dough will be slightly sticky. Knead a few times on a floured surface and roll out to around a 15" round. Transfer the dough to a large piece of parchment paper that has been dusted with semolino flour. Place on a large baking sheet. Sprinkle the center area of the dough with more semolino.
Filling:
6 - 8 medium size tomatoes, cut into 1/2" slices and placed on paper towels and lightly salted.
4 oz. Gruyere cheese, coarsely grated
1/3 cup mayonnaise
1/4 cup of finely chopped herbs (combination of basil, parsley and chives)
Ground pepper to taste
Mix together 2 oz. Gruyere cheese, the mayonnaise and herbs along with the ground pepper.
Arrange the tomatoes, slightly overlapping on the dough, leaving a 1 1/2" border. Sprinkle with 2 oz. Gruyere cheese. Arrange another layer of tomatoes. Dollop generous portions of the cheese, mayo and herb mixture over the tomatoes. Fold the dough border over the edges of the tomatoes, pleating the dough as you go.
Bake in a 425 degree oven for 30 minutes or until the crust is golden-brown. Let cool on a wire rack before cutting into wedges.