Soft, fluffy muffins studded with juicy blueberries, raspberries, strawberries, and blackberries. Bakery-style golden tops, tender crumb, and an easy batter that uses pantry staples—perfect for breakfast, brunch, snacks, or freezing for later.
Preheat oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or lightly grease.
In a large bowl whisk together flour, sugar, baking powder, baking soda, salt, and lemon zest until evenly combined.
In a medium bowl whisk the eggs, then whisk in buttermilk, oil (or melted butter), and vanilla until smooth.
Pour the wet ingredients into the dry ingredients and stir gently with a spatula until just combined; the batter should be slightly lumpy. Do not overmix.
Toss the mixed berries with 1 tablespoon flour, then gently fold them into the batter to distribute without crushing.
Divide the batter evenly among muffin cups, filling each about 3/4 full. Sprinkle tops with coarse sugar if using.
Bake 20–25 minutes (typically 18–22 minutes for powerful ovens) until tops are golden and a toothpick inserted in the center comes out clean or with a few moist crumbs.
Cool in the pan for 5 minutes, then transfer muffins to a cooling rack to cool completely or serve warm.
Storage: Keep in an airtight container at room temperature up to 2 days or refrigerate up to 5 days. Freeze up to 3 months; thaw at room temperature or warm briefly in a 300°F oven.