DIRECTIONS
1. For the tomato filling, melt 2 tablespoons of the butter in an oven safe skillet over medium-high heat.
2. Add the onion and cook, stirring occasionally, until softened and lightly browned, about 5 minutes. Stir in the garlic, thyme, and Aleppo. Cook just until fragrant, about 1 minute.
3. Rough chop the large tomatoes and add to the skillet along with the brown sugar and 1 ¼ teaspoons salt, then let the mixture simmer until the tomatoes begin to soften and release their juices, 4 to 5 minutes. Remove the skillet from the heat and stir in the flour and cherry tomatoes until evenly combined. Dot the surface with the remaining 1 tablespoon butter.
4. For the biscuit topping, whisk together the flour, baking powder, granulated sugar, ¾ teaspoon salt, and pepper in a medium bowl. Add the sliced butter and cut into the dry ingredients until the mixture resembles coarse meal, with a few small pieces of butter still visible. Pour in 2⁄3 cup milk, then add the thyme and mustard, stirring gently just until a soft, sticky dough comes together; take care not to overmix, as a light hand makes the most tender biscuits.
5. To assemble and bake, preheat the oven to 350°F. Using an ice cream scoop or large spoon, drop generous mounds of biscuit dough evenly over the tomato filling, leaving a little space between them so the filling can bubble up around the edges. Brush the tops lightly with milk, then bake until the biscuits are golden brown and the filling is bubbling enthusiastically, 55 to 60 minutes. Let the cobbler rest for 15 minutes before serving, which allows the juices to settle and the flavors to come together beautifully. Can be served on its own or act as a side dish.