In a mixing bowl, add the flour, baking powder, salt, and cream of tarter. Mix well.

Cut the butter into 1/2 inch chunks and add to the flour mixture

Use a pastry blender, fork, or a berry masher (yes, this works really well) to cut the butter into the flour mixture. It should resemble coarse crumbs.

In a measuring cup, add the milk and vinegar together. Pour over flour/butter mixture and mix, but do not over mix - there will still be some loose flour.

Keeping the mixture in the bowl, with your hand, knead the dough gently in the bowl just a few times until the dough comes together.

Place the dough on a cookie sheet.

Roll the dough to about 1/2 inch thickness, right on the pan. Gently, with as few strokes as possible.

Use a pizza cutter or knife to cut the dough into squares.

Bake at 450 degrees for 15-20 minutes. Light colored insulated sheets take less time than dark thin ones.