Prep your pan and oven. Preheat the oven to 350°F (175°C).
Line a 12-cup muffin tin with paper liners or lightly grease it. This helps the muffins release cleanly and brown evenly.
Combine dry ingredients. In a medium bowl, whisk the white whole wheat flour, all-purpose flour, baking soda, baking powder, salt, and cinnamon. Whisking aerates the mixture and prevents clumps.
Mix wet ingredients. In a large bowl, whisk the eggs until smooth.
Add Greek yogurt, olive oil, maple syrup, milk, and vanilla. Whisk until the mixture looks glossy and uniform.
Bring the batter together. Add the dry ingredients to the wet ingredients. Use a spatula to fold gently until just combined.
A few small streaks of flour are okay; overmixing makes muffins tough.
Fold in chocolate chips. Reserve a tablespoon of chips for topping if you like. Fold the rest into the batter with minimal stirring so the crumb stays tender.
Portion the batter. Divide evenly among the 12 muffin cups, filling each about 3/4 full. Sprinkle the reserved chips on top for a bakery-style look.
Bake. Bake for 16–20 minutes, or until the tops are set and a toothpick inserted into the center comes out mostly clean (a little melted chocolate is fine).
Cool properly. Let muffins cool in the pan for 5 minutes, then transfer to a wire rack.
This prevents soggy bottoms and helps the structure set.
Enjoy. Serve warm or at room temperature. The chocolate will be perfectly melty if enjoyed within the first hour.