In a small bowl, combine the diced strawberries with 1 tablespoon of granulated sugar. Stir gently and set aside for at least 10-15 minutes to macerate.

Preheat your oven to 425°F (220°C). Line a standard 12-cup muffin tin with paper liners. For best results, grease the top of the muffin pan around each cup to prevent sticking.

In a large bowl, whisk together the all-purpose flour, 1 cup of granulated sugar, baking powder, baking soda, and salt.

In a separate medium bowl, whisk together the buttermilk, oil, eggs, and vanilla extract until smooth.

Pour the wet ingredients into the dry ingredients. Fold gently with a rubber spatula until just combined and no streaks of flour remain. The batter will be thick and slightly lumpy. Do not overmix.

Gently fold the macerated strawberries and any accumulated juices into the batter with just a few strokes until evenly distributed.

Divide the batter evenly among the prepared muffin cups, filling them almost to the top. This is essential for high domes.

Sprinkle the coarse sugar generously over the top of each muffin.

Place the muffin tin in the preheated oven and bake at 425°F (220°C) for 5 minutes. Without opening the oven door, reduce the temperature to 375°F (190°C) and continue baking for 15-18 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.

Let the muffins cool in the tin for 5-10 minutes, then transfer them to a wire rack to cool completely.