A tender, moist vegan snacking cake. The double chocolate batter is made with bananas and walnuts, then topped with a oat and walnut streusel topping. Enjoy a slice with coffee or tea.
"Flax egg": In a small bowl, whisk together flax and water. Set aside for 10 minutes to thicken.
Walnut Streusel: Add ½ cup of the oats to a food processor, pulse into powder. Transfer oats to a medium bowl. Pulse walnuts until finely chopped. Transfer walnuts to the bowl. Add remaining ½ cup (whole) oats, sugar, coconut oil, cinnamon, and salt. Stir until clumps form. Set aside.
Dry ingredients: In a large bowl, whisk together spelt flour, cocoa powder, baking powder and baking soda. Set aside.
Wet ingredients: In a medium bowl, whisk together banana, sugar, milk, coconut oil, vanilla, and salt. Add "flax egg", whisk until combined.
Combine: Add the wet ingredients to the dry ingredients. Gently mix until there are a few streaks of flour left. Gently fold in walnuts and chocolate (be careful not to overmix).
Assemble and bake: Line 1 9-inch square pan with parchment (see note 2). Pour the batter into the pan, then sprinkle the walnut streusel on top. Bake until a toothpick comes out clean, 40 to 50 minutes. Let cool, lift from pan, and cut into squares.
Notes
Milk: Non-dairy milk should be unsweetened and unflavored. Adding room temperature milk will prevent the coconut oil from solidifying. You can substitute non-dairy milk for dairy milk if you'd prefer.
Baking pan substitute: If you don't have a 9-inch pan, you can use an 8-inch pan instead (as long as it's sides are at least 2-inches tall). If using a smaller pan, you may need to gently press the streusel topping down to get it to fit.
Baking by weight: For the most reliable results, we recommend measuring by weight when baking. Ingredient weights are provided in metric. If you must go by volume (measuring cups), make sure to fluff, spoon, and level the flour to avoid adding too much.