In a large bowl, mix the almond flour, coconut flour, baking powder, and salt.

In a separate bowl, whisk the egg yolks with the heavy whipping cream, melted butter, sugar substitute, lemon zest, lemon juice, and vanilla extract. Whisk well until the mixture is smooth.

Gradually add the egg yolk mixture to the dry ingredients and whisk until a smooth, consistent batter forms.

In a clean, dry bowl, use an electric mixer to beat the egg whites until stiff peaks form. This step is important for making the waffles light and crispy.

Gently fold the beaten egg whites into the waffle batter. Use a spatula and fold with an upward motion to keep the air in the egg whites. Be careful not to overmix.

Heat your waffle iron and grease it lightly with melted butter or coconut oil to prevent sticking.

Pour a suitable amount of the waffle batter onto the hot waffle iron and close it.

Bake the waffle until it is golden brown and fully cooked. Repeat with the remaining batter.

Serve the Keto Lemon Waffles warm, garnished with unsweetened whipping cream and a few fresh berries or strawberries, if desired.