Preheat your oven to 350°F. Line a baking sheet with parchment paper and lightly spray it with oil, or use a silicone baking mat.
Add 1 cup cottage cheese to a blender or food processor and blend until completely smooth. This step is important. Any curds left behind can create wet pockets and affect how the loaf sets as it bakes.
In a large bowl, whisk together 1¼ cups oat flour, ½ cup almond flour, ¼ cup grated parmesan cheese, 1½ teaspoons baking powder, and ½ teaspoon salt until evenly combined.
Add the blended cottage cheese and 1 large egg, then mix just until a dough forms. It should feel slightly tacky but not wet. If it feels dry, add 1 to 2 tablespoons milk. If it feels too loose, sprinkle in a little more oat flour.
Lightly oil your hands and shape the dough into a smooth loaf directly on the prepared baking sheet. Aim for even thickness so it bakes evenly.
In a small bowl, lightly beat 1 egg white and brush it over the top of the loaf. Sprinkle with 1 teaspoon sesame seeds if using. This helps the crust brown and gives the loaf that classic French bread look.
Bake for 28 to 32 minutes, until the loaf is golden and feels firm when lightly pressed. Transfer to a wire rack and let it cool completely before slicing.This cooling step makes a big difference. The bread continues to set as it cools, and slicing too soon can make the center feel gummy even when it is fully baked.