Preheat the oven to 400 degrees. Line a muffin tin with muffin liners. Set that aside.
In a medium bowl, mix together the flour, baking powder, and baking soda. Set that aside.
In a large bowl, mix together the coconut oil and the sugar. Mix with a whisk until well combined.
Add the eggs, vanilla extract, and kefir to the bowl and mix well until all the ingredients are combined.
Add the dry ingredients to the wet ingredients and mix until just combine. Do not overmix. It's ok if there are a few lumps left in the batter.
With an ice cream scoop or a measuring cup, scoop the batter evenly into the prepared muffin tin.
Bake the muffins for 15-18 minutes or until a toothpick is inserted and comes out clean.
Let the muffins cool on a wire rack.