Instructions

• Preheat oven to 400°F. Line a 12-cup muffin tin with paper liners and set aside.
• In a medium bowl, whisk together 3 cups all-purpose flour, 1 tablespoon baking powder, ½ teaspoon baking soda, and ½ teaspoon salt. If using, add 1 teaspoon fresh orange zest to the dry ingredients and whisk to combine.
• In the bowl of a stand mixer (or a large mixing bowl), cream 10 tablespoons unsalted butter (room temperature) and 1.75 cups granulated sugar on medium speed until light and fluffy, about 2–3 minutes.
• Add 2 large eggs one at a time, mixing well after each addition. Scrape down the bowl as needed.
• Add 1 teaspoon vanilla extract and mix until combined.
• With the mixer on low, add the dry ingredients and 1.5 cups Greek yogurt in alternating additions, beginning and ending with the dry ingredients: add one-third of the dry mixture and mix until just combined, add half the yogurt and mix, add the next third dry and mix, add the remaining yogurt and mix, then add the final third dry and mix just until combined. Do not overmix.
• Fold in 1 cup semi-sweet chocolate chips and ½ cup chopped milk chocolate with a wooden spoon or rubber spatula until evenly distributed.
• Divide the batter among the prepared liners, filling each all the way to the top. If desired, press a few extra chocolate chips or chocolate pieces onto the top of each muffin.
• Bake at 400°F for 5 minutes. Without opening the oven, reduce the temperature to 375°F and continue baking for 15 more minutes, or until the tops are browned and a toothpick inserted into the center of a muffin comes out clean or with a few moist crumbs.
• Remove the muffins from the oven and let them cool in the pan for 2 minutes. Transfer muffins to a wire rack to cool completely.