Preheat oven to 425°F (218°C). Spray a 12-count muffin pan with nonstick spray or line with cupcake liners. Set aside.

Whisk the flour, baking powder, baking soda, and salt together in a large bowl until combined. Set aside. In a medium bowl, whisk the egg, sugar, and melted butter together until combined. Whisk in the sour cream, milk, and vanilla extract. Pour the wet ingredients into the dry ingredients, whisk a few times to begin combining, and then stir with a silicone spatula to finish combining. Batter is very, very thick. Fold in the strawberries and chocolate chips. Avoid overmixing.

Spoon the batter into liners, filling them all the way to the top. Bake for 5 minutes at 425 then, keeping the muffins in the oven, reduce the oven temperature to 350°F (177°C). Bake for an additional 17-19 minutes or until a toothpick inserted in the center comes out clean. The total time these muffins take in the oven is about 22-24 minutes, give or take. (For mini muffins, bake 12-14 minutes at 350°F (177°C) the whole time.)

Allow the muffins to cool for 5 minutes in the muffin pan, and then transfer to a wire rack to continue cooling.

In a microwave-safe bowl, melt the chocolate in 15 second increments stopping and stirring after each until perfectly smooth. (Stir in 1 teaspoon vegetable oil if chocolate seems too thick for drizzling.) Drizzle over muffins. Muffins can still be warm when adding the chocolate topping.

Allow chocolate to set completely at room temperature or in the refrigerator OR enjoy muffins while chocolate topping is still warm.

Muffins stay fresh covered at room temperature for a few days, then transfer to the refrigerator for up to 1 week.