Preheat oven to 375°F. Line a 12-cup muffin tin with paper liners or grease lightly.
In a large bowl, whisk together 2 cups all-purpose flour, ½ cup granulated sugar, 2 tsp baking powder, ½ tsp baking soda, and ¼ tsp salt.
2 cups all-purpose flour, ½ cup granulated sugar, 2 tsp baking powder, ½ tsp baking soda, ¼ tsp salt, 1 tbsp instant espresso powder
In another bowl, whisk ¾ cup whole milk, ¼ cup vegetable oil, 2 large eggs, 2 tsp vanilla extract, and 1 tbsp instant espresso powder until combined.
¾ cup whole milk, ¼ cup vegetable oil, 2 large eggs, 2 tsp vanilla extract
Pour wet ingredients into dry ingredients and gently fold until just combined. Do not overmix. Fold in the c1 cup dark chocolate chunks .
1 cup dark chocolate chunks
Divide batter evenly among the 12 muffin cups. Sprinkle the tops generously with 2 tbsp turbinado sugar for a crunchy, sparkling topping.
2 tbsp turbinado sugar
Bake for 18–22 minutes, or until a toothpick inserted into the center comes out clean.
Let muffins cool in the pan for 5 minutes, then transfer to a wire rack.