Step 1

Preheat oven to 425°F. Line 9 muffin tins with muffin cups and set aside.

Step 2

In a standing mixer fitted with a paddle attachment, cream the butter and sugar on high until light and fluffy, about 3 minutes (do this for the entire time! it will make your muffins puff up when they bake). Beat in egg for an additional minute. Beat in the greek yogurt and vanilla extract until combined.

Step 3

In a small bowl, mix together the flour, baking powder, baking soda, and salt. Incorporate into wet ingredients, mixing until it begins to come together (not fully incorporated). Fold chocolate chunks into batter, mixing only until combined. Batter will be thick.

Step 4

Scoop batter into prepared muffin tins, filling just shy of the top of the liner. Sprinkle tops with more granulated sugar. Bake for 5 minutes at 425°F, then turn oven down to 375°F and bake for an additional 15 minutes, until muffins are golden brown and spring back to the touch. Remove from oven and allow to cool for at least 5 minutes before eating!