Blend cottage cheese until smooth. In a microwave-safe mug, whisk cottage cheese and egg together with honey or maple syrup if using, until creamy.
Stir in oat flour or almond flour, baking powder, cinnamon, nutmeg, and salt. Mix gently until smooth. Fold in diced apple pieces.
Microwave 60–90 seconds until fluffy and set in the center. Do not overcook.
Rest 1–2 minutes, add Greek yogurt if using, drizzle maple syrup, and sprinkle a touch of cinnamon.
