Line 16 muffins cups with liners. I recommend silicone liners, as the muffins come out perfectly from those but stick a bit to paper liners.
Stir the wet mixture into the dry mixture just until combined. The batter will be a little lumpy, but don’t over mix!
Bake for 18 minutes until they’re golden and a toothpick inserted in the middle comes out clean. The first few minutes in the oven, I was worried as the batter had risen and spread so that the muffins were touching each other. They somehow shrunk after a few minutes and went back to normal.
Transfer the pan to a wire rack and let the muffins cool for 5 minutes and then turn out onto a wire rack. Store in an airtight container for up to 4 days.
To make dairy-free buttermilk, add 1 tablespoon of lemon juice or apple cider vinegar to a 1-cup measuring cup. Fill with dairy-free milk of choice (but not canned coconut milk as it's too thick). Let sit 5 minutes and then use in place of the buttermilk.
Adapted from Williams Sonoma.