Preheat oven to 375℉. Line muffin tin with paper liners.
In a medium bowl, whisk together the flour, oat flour, baking powder, and salt.
Put berries into a separate bowl, sprinkling 1 tsp of dry ingredients into the berries and gently toss until completely coated. This prevents them from falling to the bottom of the muffins!
In a stand mixer with a paddle attachment, or a large bowl with a hand mixer, combine butter, sugar, and lemon zest. Beat on medium-high until light, fluffy, and doubled in volume (2-3 minutes). Scrape sides down with a rubber spatula.
Reduce mixer to low and add eggs one at a time until fully incorporated, followed by lemon juice and extracts.
Add dry ingredients in halves, adding the second half only after the first half has been fully combined.
Pour milk in steady stream down the side of the bowl and beat until just combined.
Scrape down bottom and sides of the bowl, then beat on low for 30 seconds. Gently fold berries into the batter with a spatula.
Use a 3 tablespoon scoop to fill each liner.
Bake for 30 minutes, or until muffins are domed and golden brown around the edges and a skewer inserted comes out with a few crumbs attached. Cool for 10 minutes in the tin and serve warm or room temperature.