Cornbread Coffee Cake with Fresh Figs and Walnut Streusel

Name: Cornbread Coffee Cake with Fresh Figs and Walnut Streusel
Ingredients: For the Walnut Streusel:; 2/3 cup sliced walnuts (or any nut you like, really); 2/3 cup light brown sugar, packed; 1/2 cup rolled oats; 1/4 cup whole wheat flour; 1 teaspoon cinnamon; 1/2 teaspoon salt; 8 tablespoons (1 stick) cold unsalted butter, cut into pieces; For the Cornbread Cake:; 1/2 cup plus 2 teaspoons room-temperature butter, divided; 3 cups figs, divided; 2/3 cup granulated sugar; 2 large eggs; 1 1/2 cups cornmeal; 1 cup whole wheat flour; 2 teaspoons baking powder; 1/2 teaspoon baking soda; 1 1/2 cups buttermilk; 1/4 cup apple cider; 1 teaspoon vanilla paste or extract; 1/2 cup sour cream