Preheat your oven to 350°F (175°C) and prepare an 8x8-inch baking pan by lining it with parchment paper or greasing it.

In a large bowl, whisk together the wet ingredients: ½ cup of butter and ½ cup of sweetener until smooth and creamy.

In another bowl, combine the dry ingredients: 2 cups almond flour, ¼ cup tapioca flour, and 1 teaspoon cinnamon. Whisk until there are no lumps.

Fold the dry ingredients into the wet mixture gently, then stir in 1 cup of fresh blueberries.

For the streusel, mix ¼ cup coconut sugar, ½ cup almond flour, and 2 tablespoons of softened butter; work into a crumbly texture.

Spread the cake batter into the prepared baking pan and sprinkle with streusel topping, pressing lightly.

Bake for 35-40 minutes until golden brown and a toothpick comes out clean.

Allow the cake to cool in the pan for 10-15 minutes, then transfer to a wire rack to cool completely or enjoy warm.