Preheat the oven to 350°F. Grease an 9×9-inch baking pan or line with parchment.
Combine all of the crumb topping ingredients in a small bowl with a fork until crumbly and set aside.
Add flour, baking powder, baking soda, salt and pumpkin pie spice to a medium mixing bowl and stir to combine.
Whisk together eggs, pumpkin puree, coconut sugar, Greek yogurt, coconut oil and vanilla in a large mixing bowl.
Add the flour mixture to the wet mixture and stir until just combined.
Add cake batter to the prepared pan and sprinkle with the crumb topping.
Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean, or with just a few moist crumbs sticking to it.
Let cake cool for about 15 minutes before serving.
While cake is cooling, make icing by whisking together powdered sugar, vanilla extract and almond milk in a small bowl.
Drizzle icing over warm cake. Cut into squares and serve!