Preheat oven to 375°F. Line a 12-cup muffin tin with paper liners or lightly grease with cooking spray and set aside.
In a large bowl, whisk together flour, sugar, baking powder, and salt.
In a separate bowl, beat the eggs, oil, vanilla extract, and milk until smooth.
Pour the wet ingredients into the dry and stir until just combined. Do not overmix.
Toss chopped strawberries and blueberries with 1 tablespoon of flour. Gently fold into the batter.
Scoop the batter into the muffin tin, filling each cup about ¾ full.
Bake for 18–22 minutes, or until a toothpick inserted in the center comes out clean. Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely. Enjoy!