Preheat oven to 350 degrees Fahrenheit. Line the bottom of two 6-inch baking sheets with parchment paper. Lightly grease the bottoms and sides.
In a small bowl, combine the strawberries, lemon juice, lemon zest, and 1 tbsp monk fruit sweetener. Set aside.
In a separate bowl, sift together almond flour, protein powder, coconut flour, baking powder, and salt.
In a large bowl, use an electric mixer to whip together the eggs and egg white until foamy. Then, add 1/4 cup monk fruit sweetener and beat until mixture has thickened, about 3-5 minutes. Gently fold in dry ingredients followed by the kefir, melted butter, and vanilla extract. Add stevia drops or monk fruit drops to taste.
Pour batter evenly into the pan(s). Bake for 12-15 minutes for two 6-inch cake pans, or 20-25 minutes for one 8-inch pan.
Meanwhile, combine all whipped cream ingredients in a medium bowl. Whip using an electric mixer until fluffy.
Once cakes are done, flip them over onto a wire rack. Let the cakes cool completely. If using one big cake instead of two smaller ones, cut the big cake in half.
Assemble the strawberry shortcake. Start with one layer of cake and spread on half of the whipped cream. Add half of the strawberries, and stack another cake on top. Top with the rest of the whipped cream and strawberries.