Preheat oven to 350° F and line muffin pan with muffin liners.

Stir together vinegar, non-dairy milk, and flax meal and set aside. This is your vegan buttermilk.

In a large bowl, whisk together all dry ingredients (including chocolate chips), except for sugar. Set aside.

In a standmixer, using the paddle attachment (you can also use a hand mixer), mix vegan butter and sugar until light yellow on medium high. Add pumpkin puree, vanilla extract, and vegan buttermilk. Continue mixing on medium and gradually mix in dry ingredients in three parts. Be sure to take a rubber spatula down the sides of the bowl to make sure all the flour is incorporated.

Using ice cream scooper or two spoons, scoop muffin batter (which will be a thick paste) into muffin liners. Smooth out the tops with the back of a spoon as much as possible before placing in the center rack of the oven.

Bake for approximately 18-22 minutes until toothpick comes out clean. Once removed from the oven, let them rest in the muffin pan for approximately 10 minutes before removing them to enjoy!