3pounds fresh tomatoes (8-10 medium), cut into wedges
2 tablespoons cornstarch
Salt and pepper
1cup all-purpose flour, plus more if needed
1cup cornmeal
1 1/2 teaspoons baking powder
1/4 teaspoon baking soda
4 tablespoons (1/2 stick) butter, cut into large pieces and very cold
1 egg, beaten
3/4cup buttermilk, plus more if needed
Instructions
Grease a 13 × 9-inch baking dish with the oil or butter. Heat the oven to 375°F.
Put the tomato wedges in a large bowl and sprinkle with the cornstarch and some salt and pepper. Toss gently to combine.
Put the flour, cornmeal, baking powder, and baking soda in a food processor along with a teaspoon salt. Add the butter and pulse a few times until the mixture looks like coarse bread crumbs. Add the egg and buttermilk and pulse a few times more, until the mixture comes together in a ball. If the mixture doesn’t come together, add a spoonful or 2 more flour. If the mixture is too dry, add a few more drops buttermilk.
Gently toss the tomato mixture again and spread it in the bottom of the prepared baking dish. Drop spoonfuls of the dough on top and smooth a bit with a knife. Try to leave some gaps so the steam from the tomato mixture will have a place to escape as the cobbler bakes. Bake until golden on top and bubbly underneath, 45 to 50 minutes. Cool to just barely warm or room temperature. To serve, scoop portions out with a large spoon.