Preheat oven to 425°F. Line a baking sheet with a silicone mat or parchment.
Combine plant milk and vinegar and allow to sit while you measure your remaining ingredients. It will curdle and act as your vegan "buttermilk."
Food processor method: In the bowl of a food processor, add flour, baking powder, garlic powder and salt and pulse to combine. Add in cubed butter and pulse several times. Then add in vegan cheddar shreds and continue to pulse until the mixture resembles coarse crumbs, with pea-sized bits of butter. By hand: In a large bowl, whisk together flour, baking powder, garlic powder, and salt. Add in cubed butter and vegan cheddar shreds and use a fork or pastry cutter to cut butter into pea-sized bits.
Food processor method: Drizzle in "buttermilk" while pulsing. Continue to pulse until mixture comes together and pulls away from sides of food processor. Do not over-process. By hand: Drizzle "buttermilk" into dry mixture while gently mixing with a wooden spoon or spatula. Continue to stir until mixture just comes together.
Turn dough out onto a lightly floured surface. Pat the dough down with your hands into a small rectangle, then fold it in half. Repeat 2 more times to create extra flaky layers.
Pat or roll dough out one more time to roughly 1" thickness. Use a biscuit cutter to cut out your biscuits. You can press together your leftover dough, pat back out to 1" thick and cut out a few extra biscuits.
Arrange biscuits on lined tray. Bake 15-18 minutes, or until browned. Optionally, brush with melted butter after removing from oven.