Preheat oven to 350F and spray or butter an 8 x 8 baking pan
In a large bowl, combine the pumpkin purée with the melted butter, brown sugar, and coconut milk. Mix together and stir in the pumpkin spice, vanilla, and cinnamon.
Gently fold in the flour, baking powder, baking soda, and salt. Mix until batter is just combined. It will be thick.
Spread half of the cake batter into your prepared pan.
Make the filling for the middle layer. In a small bowl, combine the flour, brown sugar, and cinnamon. Sprinkle the mixture on top of your cake.
Spread your remaining cake batter on top, then prepare the topping. In a small bowl, combine the flour, brown sugar, cinnamon, and nuts. Mix in the melted butter and combine until the mixture is clumpy and crumbly. Sprinkle on top of the cake.
Bake the cake in the preheated oven for 45 min. I covered mine after about 35 min so it didn’t get too brown on top.
To serve, top with powdered sugar or the glaze.
For the glaze, just mix the powdered sugar with the milk, adding it a little bit at a time. You may or may not need it all. Stir in the vanilla extract, then drizzle on your coffee cake. Enjoy!