In a suitable cup, mix the instant dry yeast, sugar, and lukewarm water, and let it sit for about 10 minutes. Preheat the oven to 430°F with the baking sheet inside.

In another cup, mix the milk and lemon juice (for ease, add 1 teaspoon of lemon juice to a measuring cup and fill with milk to the 1/4 cup mark).

In a dry bowl, add all the dry ingredients and mix with a whisk to remove lumps. Add the margarine and cut it in with the whisk.

It's okay if it doesn't become as fine as breadcrumbs like scones; pea-sized pieces are fine.

Add the yeast mixture and milk, and gently mix in a sprinkling motion. Turn the dough out onto a floured piece of plastic wrap.

Sprinkle flour on top of the dough, cover with another piece of plastic wrap, and gently press and fold the dough with your hands until it comes together.

Cut into 4 pieces, place on a baking sheet, and bake for 12-15 minutes.