Mix lemon juice together with plant milk. This is your vegan buttermilk.
Sift together flour, baking powder, baking soda, salt, coriander, and lemon zest.
In a separate bowl, using a hand mixer, cream together butter with sugar. To the creamed butter, add your vegan buttermilk, along with vanilla extract and aquafaba (or more plant milk).
Add dry ingredients to wet ingredients until all dry ingredients have been incorporated (don't overmix!). Gently fold in blueberries with a spatula so they don't burst (if they do, don't worry! You'll have beautiful swirls in your muffins!). The batter will be thick and sticky.
Using two spoons or an ice cream scooper, scoop batter into each greased muffin pan until each "cup" is 3/4 full.
Place in the oven for 10 minutes. Then lower the temperature to 350 degrees F for another 15 to 18 minutes or until toothpick comes out clean.
Notes
If you want smaller muffins, you can bake up to 12 muffins, but as I said, I like my muffins FAT.