Place a rack in the center of the oven. Preheat your oven to 375°F (190°C) and grease or line a muffin tin with paper liners.
In a medium mixing bowl, whisk the whole wheat flour, cornstarch, baking powder, baking soda, and salt. Set aside.
2¼ cups whole wheat flour, 2 TBS cornstarch, 2 tsp baking powder, ½ tsp baking soda, ½ tsp salt
In a large bowl using an electric hand mixer, beat the eggs and coconut sugar together for 3 - 5 minutes. The mixture should become a light caramel color and have increased in volume. This step both dissolves the coconut sugar so it incorporates evenly throughout the batter and helps the muffins be fluffy.
2 large eggs, ½ cup coconut sugar
Next, beat in the yogurt, oil, and vanilla.
1 cup plain yogurt, ½ cup avocado oil, 1 TBS vanilla
Gently mix the dry ingredients into the wet ingredients.
Fold the chocolate chips into the batter.
1 cup chocolate chips
Divide the batter evenly among the muffin cups, filling each a little over ¾ full. Filling each muffin cup nearly full helps the muffins develop a classic domed muffin top.
Bake for 22 - 25 minutes.
Let the muffins cool in the pan for about 5 minutes, then transfer them to a wire rack to cool completely. These muffins are perfect for breakfast, brunch, or as a snack.