Preheat oven to 350 degrees. Grease a 9x13 inch pan with cooking spray and set aside.
To make the cake: Using an electric mixer or wooden spoon, mix butter, brown sugar pumpkin, and eggs together until smooth. Add the flour, baking powder, salt, and spices. Mix until just combined and pour evenly in prepared baking dish.
To make the topping: Combine flour, white sugar, brown sugar, cinnamon, and melted butter. Crumble with your fingers and sprinkle on top of the cake. Bake for 35-40 minutes or until center comes out clean when a toothpick is inserted.
To make the glaze: Place the butter in a medium sized saucepan and melt over medium low heat. Bring temperature to medium and continue to stir until butter starts to foam and turns brown. Remove from heat.
In mixing bowl, add powdered sugar, vanilla, and maple syrup. Add brown butter and mix until smooth. If it is thick, I put mine in the microwave for about 20 seconds so that it could easily drizzle over cake.