Preheat your oven to 375°F (190°C). Line a 24-cup mini muffin tin with paper liners or lightly grease with baking spray—this helps the muffins slip right out.

In a large bowl, whisk together flour, sugar, baking powder, and salt. Make sure the baking powder is evenly distributed for consistent lift.

In a separate bowl, beat the egg lightly. Stir in milk, melted butter, and vanilla until the mixture looks smooth and glossy.

Pour the wet mix into the dry ingredients. Gently fold with a spatula—overmixing leads to tough muffins. A few streaks of flour are okay.

Tip in the berries and swirl them through the batter just enough so you see pretty purple ribbons. If you want a pop of lemony zing, fold in lemon zest here.

Use a small cookie scoop or two spoons to portion about 2 tablespoons of batter into each mini cavity—fill roughly ¾ full.

Slide the tin into the oven and bake for 12–14 minutes, rotating halfway through. You’re aiming for firm tops and golden edges. A toothpick inserted in the center should come out clean or with a couple of moist crumbs.

Let the muffins rest in the tin for 5 minutes—this prevents breakage—then transfer to a rack. They’ll keep their shape (and moisture) better that way.