01 - Preheat oven to 400°F. Line a 12-cup muffin tin with paper liners or grease thoroughly.
02 - In a large bowl, whisk together flour, baking powder, baking soda, and salt until well combined.
03 - In a separate bowl, whisk oil or melted butter, sugar, eggs, milk, and vanilla extract until smooth and fully incorporated.
04 - Pour wet ingredients into dry ingredients. Gently fold together until just combined—batter should remain slightly lumpy. Avoid overmixing to prevent tough muffins.
05 - Gently fold diced strawberries into batter until evenly distributed.
06 - Divide batter evenly among prepared muffin cups, filling each about three-quarters full.
07 - Sprinkle coarse sugar generously over the top of each muffin.
08 - Bake for 22 to 25 minutes until tops are golden brown and a toothpick inserted into the center comes out clean.
09 - Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.