Preheat the oven to 350F. Line an 8x8 inch square baking dish with parchment paper and grease it lightly.
Start with the streusel. In a bowl, mix the gluten free flour, oats, almond flour, salt, cane sugar, cinnamon, and pumpkin pie spice. Pour in the melted butter and pinch it together with your fingers until it forms clumps. Set it aside.
In a large bowl, whisk the gluten free flour, baking powder, pumpkin pie spice, cinnamon, salt, and cane sugar.
In another bowl, stir together the cottage cheese, pumpkin puree, vanilla, eggs, and olive oil. I don't blend the cottage cheese here. It goes in as it is.
Add the wet ingredients to the dry and mix until just combined. The batter will be very thick, so switch to a spatula if the whisk gives up.
Spread half of the batter in the baking dish and level it out. Sprinkle half of the streusel on top.
Spoon over the rest of the batter and level it out again. Finish with the remaining streusel.
Bake for about 50-55 minutes, until a toothpick in the center comes out clean.
Let it cool down for at least 1 hour inside the baking form.
Stir the Greek yogurt, milk and maple syrup together until smooth. Drizzle it over the cooled cake and slice into 16 squares.