Lightly toast the keto or protein bread in a toaster or dry skillet just until the surface feels slightly firm but not browned. This step improves structure and prevents the bread from becoming soggy once the cheese starts melting, especially with high-protein or keto breads.

Lay one slice of bread on a cutting board and evenly layer the cheese over the surface. If using blended cottage cheese for extra protein, spread a thin, smooth layer first, then add the sliced cheese on top. Finish with the second slice of bread, pressing very gently so the filling stays in place.

Place a skillet over medium-low heat and add the butter. Let it melt completely and coat the bottom of the pan. The heat should be steady and moderate — too hot will brown the bread before the cheese melts.

Carefully place the sandwich into the skillet and cook slowly. Let it sit undisturbed for a few minutes until the bottom turns deep golden and crisp. Avoid pressing too hard, as this can squeeze the cheese out before it melts.

Use a wide spatula to flip the sandwich gently. Cook the second side on medium-low heat until the bread is golden and the cheese inside is fully melted and stretchy. If needed, briefly cover the pan to help the cheese melt without over-browning.

Remove the sandwich from the skillet and let it rest for about one minute. This short rest allows the cheese to settle slightly, making it easier to slice. Cut in half and serve warm while the center is perfectly melty and the exterior stays crisp.