Preheat oven to 350° F.

Lightly coat 8 x 4-inch loaf pan with spray; set aside.

Separate egg yolks from egg whites; place in separate medium mixing bowls. Use a whisk or hand mixer to beat egg whites until soft peaks form; set aside.

Finely grate lemon peel; set aside.

Combine egg yolks, lemon zest, applesauce, maple syrup, and vanilla in a medium mixing bowl; mix well. Set aside.

Combine almond flour, tapioca flour, baking powder, cardamom, and salt in a large mixing bowl; mix well. Set aside.

Pour egg mixture into almond flour mixture; mix until a smooth batter forms.

Gently fold egg whites into batter.

Pour batter into prepared pan; bake for 45 to 50 minutes, or until a toothpick inserted into center comes out clean.

Cool for 5 minutes; turn loaf out onto cooling rack. Let cool completely before cutting into ten equal slices.