In a large mixing bowl, whisk together 2 cups all-purpose flour, 3 tablespoons granulated sugar, 2 teaspoons baking powder, and 1 teaspoon kosher salt until evenly combined.

Cut 6 tablespoons cold unsalted butter into small cubes and add to the flour mixture. Using a pastry blender, two forks, or your fingertips, cut the butter into the flour until the mixture resembles coarse crumbs with some pea-sized bits of butter remaining.

Wet Mix & Combine

In a separate bowl, whisk together 1 cup whole milk, 1 large egg, and 1 teaspoon vanilla extract until smooth and slightly frothy.

Make a well in the center of the dry ingredients and pour the wet mixture into it. Stir gently with a spatula or wooden spoon just until combined — the batter should be slightly lumpy. Do not overmix to keep the final texture tender.

Fold in 1 cup fresh blueberries (or chocolate chips) gently so they are evenly distributed without crushing them.

Baking & Finish

Spoon the batter into the prepared pan and smooth the top with a spatula. If desired, sprinkle 1 tablespoon turbinado or coarse sugar over the top for a crunchy finish.

Bake in the preheated 425°F (220°C) oven for 18–22 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean or with a few moist crumbs.

Remove the pan from the oven and let cool on a wire rack for 10–15 minutes. If using a round pan, run a knife around the edge to loosen and transfer the cake or slice directly from the pan.

Serve warm, optionally with butter and maple syrup or honey to taste.