Preheat oven to 400 F (200 C) for conventional oven, 380 F (190 C) for convection oven. Line your 12-well muffin pan with cupcake liners
Prepare the muffin batter:
Combine all the dry ingredients and set aside. In a mixing bowl, whisk the eggs and sugar until the sugar melts, add Greek yogurt or sour cream, orange extract, orange zest and oil. Whisk to combined
Sift in the flour mixture.
Add the chocolate chips and fold until you no longer see any loose pockets of flour. It is important not to overmix the batter or the muffins will turn out dense
Scoop the muffin batter into each cup, filling it all the way to the top
Baking:
Bake in the preheated oven, middle rack for 15-17 minutes or until the top is dry to touch and spring back when you touch lightly. A toothpick inserted should come out pretty clean with some crumbs, but nothing should be wet. DO NOT overbake the muffins or they will be dry and tough
Let them cool down in the pan for 5 minutes (Do not skip this step). Then transfer to a cooling rack to let them cool down completely
Storing:
Once the muffins have cooled down completely, store them in an air-tight container or in a zipper bag, push all the air out and seal. They stay fresh at room temperature for 2-3 days.
To freeze them, I usually individually wrap each muffin with a cling wrap and them seal them in a freezer bag and keep in the freezer for up to one month. To serve, simply thaw at room temperature before serving