Preheat oven to 450°F.
In a medium bowl, mix the flour, baking powder, and salt, and cut in the butter until the mixture is the consistency of coarse cornmeal.
Add the soy milk, and stir just until the dough comes free from the sides of the bowl.
Turn the dough onto a floured board, shape into a ball, and gently knead 10 times.
Roll dough out ½-inch thick, and cut with a 2-inch biscuit cutter dipped in flour.
Brush the tops of the biscuits lightly with a little soy milk.
Place the biscuits on an ungreased baking sheet.
Bake until lightly browned, 14-16 minutes.