FEEDS 10 TO 12
A slump is one of the lesser-known old-fashioned cooked fruit desserts. It is essentially a stovetop cobbler, made in a covered pot, so the topping is steamed rather than baked. I have you cook it over a flame, indoors or outdoors, but if you find it more convenient, you can bake it in a 350°F oven for 40 minutes and call it a cobbler instead.
To make this for a crowd, double or quadruple (depending on the size of your crowd) the filling and the topping and use the biggest vessels you have. A lidded Dutch oven works best but you could also use a flameproof baking dish, covered tightly with aluminum foil.
Feel free to substitute blueberries, boysenberries, huckleberries, or a mix of berries for the blackberries.
For the Filling
2 tablespoons CORNSTARCH
8 cups fresh BLACKBERRIES, rinsed and drained
1 cup SUGAR
Grated zest of 1 LEMON plus 1 tablespoon LEMON JUICE
Grated zest of 1/2 ORANGE
1/4 teaspoon ground CINNAMON
For the Topping
11/2 cups all-purpose FLOUR
3 tablespoons SUGAR
11/2 teaspoons BAKING POWDER
3/4 teaspoon BAKING SODA
1/2 teaspoon KOSHER SALT
3 tablespoons UNSALTED BUTTER, melted
3/4 cup well-shaken BUTTERMILK
For the Cinnamon Sugar
1/2 cup SUGAR
1 teaspoon ground CINNAMON
1 recipe BUTTERMILK ICE CREAM for serving
To make the filling, whisk the cornstarch with 1/4 cup water to make a slurry. Combine the berries, sugar, lemon zest and juice, orange zest, and cinnamon in a large Dutch oven.
Cook the berries over medium-high heat until they begin to break down, 2 to 3 minutes. Gently stir in the slurry and bring to a simmer. Reduce the heat to low and cook for 10 to 15 minutes, until the liquid begins to thicken.
To make the topping, combine the flour, sugar, baking powder, baking soda, and salt in a large bowl. Add the melted butter and buttermilk and stir to incorporate.
Drop golf ball–size spoonfuls of the batter onto the berry mixture, leaving about 1/2 inch between spoonfuls, as the topping will spread as it cooks. Stir the sugar and cinnamon together and sprinkle the mixture liberally over the topping. (You may not need it all.)
Place the lid on the pot or cover it tightly with aluminum foil and cook over medium heat until a toothpick inserted in the topping comes out clean, 20 to 25 minutes. Uncover the pot and let the slump cool for at least 15 minutes before serving. Serve warm with buttermilk ice cream.
To cook the slump using the cinder block pit (see Building a Cinder Block Pit, Step 8) or on a gas grill, combine the slurry and filling ingredients per the instructions in the recipe and put the pot(s) over the outdoor fire. Add the topping, cover the pot(s), and cook for about 30 minutes, until the topping is done (a toothpick inserted into the topping will come out clean).