Preheat the oven to 375°F (190°C) and line a muffin tin with paper liners.
In a large mixing bowl, whisk together the 2 cups of flour, sugar, baking powder, baking soda, salt, and orange zest.
2 cups (250 grams) plus one tablespoon all-purpose flour, ½ cup (100 grams) granulated sugar, 2 teaspoons baking powder, ½ teaspoon salt, ¼ teaspoon baking soda, zest of one small orange
In a medium bowl, combine the yogurt, eggs, vanilla extract, and orange juice and whisk until smooth.
1 cup low-fat yogurt, 2 eggs, 1 teaspoon vanilla extract, juice of one small orange
Pour the wet ingredients from the bowl and the melted butter into the dry ingredients and stir just until all visible flour has been stirred in. Do not over-mix.
½ cup (1 stick or 113 grams) unsalted butter
Toss the blueberries in the extra tablespoon of flour, and then gently fold the blueberries and chocolate chips into the muffin mixture.
½ cup blueberries, ½ cup chocolate chips
Use a large cookie scoop or spoon to divide the batter evenly among the muffin cups, filling each about ¾ full.
Bake for 18 to 20 minutes or until a toothpick inserted into the center of a muffin comes out clean.
Allow the muffins to cool in the muffin pan for 10 minutes before serving, or transfer them to a wire rack to cool completely.