Add the vinegar and vanilla to the plant milk, and mix together. This is also the time to add any zest and additional extract that you are using.
Combine the gluten free flour blend (or wheat flour plus The Plant Based Egg), baking powder, and salt in a medium-sized mixing bowl. Stir together. Add the sugars and stir again.
Melt your vegan butter, add it to the sour milk mixture, and whisk together.
Make a well in the flour mixture, then pour the liquid mixture into the well. Be sure to scrape all of it into the bowl. Whisk together until combined. You don’t have to worry about over-mixing with gluten free muffins, but be careful if you are using wheat flour.
Fold in your mix-ins. You can use any combination that you like, but keep the total volume to about 1 1/2 cups. If you are using frozen blueberries or blackberries, keep them frozen until you are ready to add them. This really helps to prevent them from coloring your batter.
Divide the batter evenly among your muffin liners. Add sugar, chopped nuts, or a crumb topping if you wish. Sugar can just be sprinkled on top, but nuts or crumb topping should be lightly pressed onto the batter.
For mini muffins, bake for five minutes at 450 degrees Fahrenheit, then reduce the temperature to 400 and bake for an additional 10 to 12 minutes, until the tops are golden brown and bounce back when lightly pressed.
For regular-size muffins, bake for five minutes at 450 degrees Fahrenheit, then reduce the temperature to 400 and bake for an additional 13 to 16 minutes, until the tops are golden brown and bounce back when lightly pressed.
For jumbo muffins, bake for five minutes at 450 degrees Fahrenheit, then reduce the temperature to 375 and bake for an additional 21 to 24 minutes, until the tops are golden brown and bounce back when lightly pressed.
For all muffin sizes, keep the oven door shut until you need to check for doneness. You do not need to rotate the pan and opening the door lets too much heat out of the oven.
Also, if you are using frozen berries, increase the cooking time by one to two minutes for mini muffins, two to three minutes for regular muffins, and three to five minutes for jumbo muffins.
Place the pan on a rack and let the muffins cool in the pan for a few minutes before removing them to the rack to finish cooling. Let your muffins cool down completely, or serve them slightly warm.
The muffins freeze and defrost beautifully, so freeze any muffins that you won't eat by the next day. To defrost, place three mini muffins or one regular or jumbo muffin upside down in the microwave. Heat on 50% power for 45 to 90 seconds (less for mini and more for jumbo), then turn the muffin right side up and heat on 50% power for another 30 to 60 seconds until the muffin is defrosted and warm all the way through.