01 - Preheat oven to 375°F. Line a 12-cup muffin tin with paper liners or grease lightly with cooking spray.
02 - In a large mixing bowl, whisk together flour, cocoa powder, sugar, baking powder, baking soda, and salt until well blended.
03 - In a separate medium bowl, whisk eggs, milk, vegetable oil, and vanilla extract until smooth and fully incorporated.
04 - Pour wet ingredients into dry ingredients. Using a spatula, fold gently until just combined—do not overmix or muffins will become tough.
05 - Gently fold diced strawberries and semi-sweet chocolate chips into batter until evenly distributed.
06 - Divide batter evenly among muffin cups, filling each about three-quarters full. Sprinkle mini chocolate chips on top if desired.
07 - Bake for 18 to 22 minutes until a toothpick inserted into center comes out with a few moist crumbs.
08 - Let muffins cool in tin for 5 minutes, then transfer to wire rack to cool completely before serving.