To prepare a whole wheat walnut crumb cake baked goods recipe, first you'll need to prepare your ingredients. First, preheat your oven to 350?F (180?C) and grease and flour two 9-inch cake pans. Then, mix together the flour, baking powder, sugar, salt, and baking soda. Add the dry ingredients to the wet ingredients and mix until just combined. Pour the batter into the prepared pan and bake the cake for 35 to 40 minutes or until the toothpick inserted in the center comes out clean.