Prep the pan and oven. Heat the oven to 350°F (175°C). Line a 12-cup muffin tin with liners or grease lightly.
This prevents sticking and helps muffins release cleanly.
Mix the dry ingredients. In a large bowl, whisk oat flour, almond flour, protein powder, baking powder, and salt. Break up any lumps so the batter stays smooth.
Whisk the wet ingredients. In a separate bowl, whisk eggs, Greek yogurt, milk, maple syrup or honey, and vanilla until well combined.
Combine wet and dry. Pour the wet mixture into the dry ingredients. Stir with a spatula until just combined.
The batter should be thick but scoopable. Avoid overmixing.
Fold in strawberries. Gently fold in the diced strawberries. If they’re very juicy, pat them dry first to keep muffins from getting soggy.
Make the cheesecake swirl. In a small bowl, beat softened light cream cheese with 2 tablespoons Greek yogurt, 1–2 tablespoons sweetener, and optional lemon zest until smooth and creamy.
Fill the cups. Divide the muffin batter evenly among the 12 cups (about 3/4 full).
Dollop 1 teaspoon of the cheesecake mixture on top of each, then use a toothpick to gently swirl it into the batter.
Bake. Bake for 18–22 minutes, or until the tops are set and a toothpick comes out with a few moist crumbs. Avoid overbaking; protein muffins dry quickly.
Cool. Let muffins cool in the pan for 5 minutes, then transfer to a rack. Cool completely before storing so condensation doesn’t make them soggy.
Taste and adjust. If you prefer a sweeter muffin, drizzle a touch of honey on warm muffins or add a few extra strawberry pieces on top.