Make the batter: In a bowl, whisk 1 cup almond flour, 1 tablespoon coconut flour, 1 teaspoon baking powder, and a pinch of salt.
In another bowl, whisk 2 eggs, 2 tablespoons melted butter, 2 tablespoons sugar-free maple syrup, 2–3 tablespoons unsweetened almond milk, and 1/2 teaspoon vanilla. Combine wet and dry until smooth and scoopable, not runny. Add a splash more almond milk if too thick.
Preheat the skillet: Heat a nonstick skillet over medium-low.
Lightly butter the surface. If using ring molds, grease them too and set them in the pan to warm.
Cook the pancake buns: Spoon batter into two small circles (or into ring molds), about 3–4 inches wide. Cook 2–3 minutes until the edges look set and bubbles form.
Flip gently and cook another 1–2 minutes until golden. Transfer to a plate and keep warm. Repeat with remaining batter for more sandwiches.
Shape and cook the sausage: Form 1/4-pound patties to match the bun size (thinner is better).
Season lightly if needed. Cook in the same skillet over medium heat, 3–4 minutes per side, until browned and cooked through. Set aside.
Fry or scramble the egg: Add a little butter to the skillet.
Crack in an egg and cook to your preference (over medium is great). Season with salt and pepper. If you prefer, scramble or make a folded egg.
Assemble: Place a pancake bun on a plate.
Add the sausage patty, top with a slice of cheese, then the egg. If you like a touch more sweetness, add a light drizzle of sugar-free syrup. Cap with the second pancake bun.
Serve hot: Press gently so the cheese starts to melt.
Eat right away for the best texture and flavor.