Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper.
In a large bowl, whisk together almond flour, coconut flour, sugar, baking powder, and salt.
Cut in the cold butter until the mixture resembles coarse crumbs.
In another bowl, whisk together eggs, heavy cream, and vanilla extract.
Add the wet ingredients to the dry ingredients and mix until just combined.
Gently fold in the blueberries and lemon zest.
Drop dough by large spoonfuls onto the prepared baking sheet.
Bake for 18-20 minutes, or until golden brown.
Let cool on a wire rack before serving.