Preheat your oven to 350°F (175°C). Grease a 9-inch round springform pan and line the bottom with parchment paper.

In a medium bowl, whisk together the gluten free all-purpose flour, baking powder, baking soda, and salt until evenly combined. Set aside.

In a large mixing bowl, beat the softened butter and granulated sugar with an electric mixer for 3 to 4 minutes until light and fluffy.

Beat in the eggs one at a time, mixing well after each addition. Then stir in the vanilla extract.

Add half of the dry mixture into the batter, mixing gently. Then add in the sour cream, blending until smooth. Finally, add the remaining dry ingredients and mix just until combined.

In a small bowl, stir together the brown sugar, cinnamon, and flour for the cinnamon filling.

Spread half of the batter in the prepared pan. Gently sprinkle the cinnamon filling over it, then carefully spread the remaining batter on top.

In a separate bowl, combine the crumb topping ingredients, then sprinkle this over the cake.

Bake for 45 to 55 minutes, or until a toothpick inserted in the center comes out clean.

Cool in the pan for at least 20 minutes. Remove from the springform ring, slice, and serve.