Preheat oven to 350°F (175°C) and grease an 8-inch round cake pan.

Toast pecans in a dry skillet over medium heat for 3–4 minutes until fragrant. Set aside to cool.

Mix dry ingredients: In a bowl, whisk together almond flour, coconut flour, baking powder, cinnamon, and salt.

Cream butter and sweetener: Beat softened butter and granulated keto sweetener until light and fluffy.

Add eggs one at a time, beating well after each addition.

Incorporate wet and dry ingredients: Alternately add the dry ingredients and heavy cream, mixing until smooth.

Fold in vanilla and pecans gently.

Pour batter into the prepared cake pan and smooth the top.

Bake for 25–30 minutes or until a toothpick inserted in the center comes out clean.

Cool cake in the pan for 10 minutes, then transfer to a wire rack to cool completely.

Make the butter pecan glaze: Melt butter in a pan, add chopped pecans and keto sweetener, and cook until golden.

Drizzle the glaze over the cooled cake before serving.