Preheat and prep. Heat your oven to 400°F (200°C). Line a 12-cup muffin pan with paper liners or lightly coat with nonstick spray.

Mix the dry. In a medium bowl, whisk 3/4 cup white whole wheat flour, 3/4 cup oat flour, 1 1/2 teaspoons baking powder, 1/4 teaspoon baking soda, 1/4 teaspoon salt, and 1/2 teaspoon cinnamon.

Whisk the wet. In a large bowl, whisk 1/2 cup plain nonfat Greek yogurt, 1/3 cup unsweetened almond milk, 1 large egg, 1 tablespoon light olive oil, 1 teaspoon vanilla, and 1/3 cup granulated sweetener. Add 1 teaspoon lemon zest if using.

Combine gently. Add the dry ingredients to the wet and stir with a spatula just until no dry spots remain. The batter should be thick but scoopable. If needed, add 1–2 teaspoons more milk.

Fold in berries. Toss 3/4 cup blueberries with 1 teaspoon flour (prevents sinking), then gently fold into the batter. If using frozen, do not thaw.

Portion. Divide batter evenly among the 12 cups. Aim for about 2 tablespoons per muffin. Sprinkle a few extra blueberries on top if you like.

Bake hot, then finish. Bake at 400°F for 5 minutes to help the muffins rise, then reduce heat to 350°F (177°C) and bake 8–10 more minutes. They’re done when a toothpick comes out clean or with a few moist crumbs.

Cool. Let muffins rest in the pan for 5 minutes, then transfer to a rack to finish cooling. This keeps them light and prevents sogginess.