Preheat oven to 350 degrees F (176 C). Prepare streusel by combining sugar and flour in a small mixing bowl and then cutting in Earth Balance until well combined. Spread on a baking sheet and bake for 5-7 minutes or until it turns light brown. Remove from oven and set aside. You will have leftover streusel.
Preheat electric griddle to medium heat (or about 350 degrees F), or a large skillet on the stove top. You want the surface to be hot but not screaming hot – oil shouldn’t smoke when it makes contact with the surface.
To the same large mixing bowl you used earlier, add mashed banana, baking soda, baking powder, salt, vanilla extract, flaxseed and water and whisk until well combined. Let set for a couple minutes.
Add melted Earth Balance and almond milk and stir.
Next add flour and stir until just combined. If your batter appears too thin, add a bit more flour, or if too thick, add almond milk. Let better rest for 5 minutes.
Lightly grease your griddle and pour 1/4-cup measurements of the batter onto the griddle.
Top with a sprinkle of streusel and walnuts and flip when bubbles appear in the middle and the edges turn slightly dry.
Cook for 1-2 minutes more on the other side and then top with an additional sprinkle of streusel, walnuts and a drizzle of maple syrup (optional).
*Because there is a whole banana in this recipe, make sure your cooking surface is on medium heat and you cook the cakes all the way through - this may mean 3-4 minutes on each side. If your skillet is too high, they'll cook too fast on the outside and stay tender on the inside.