Other than being acidic, curdled milk bears no resemblance to buttermilk, and it cannot deliver the goods. It's akin to rice cakes in lieu of hot biscuits, or, yes, water for chocolate.

Add the lard, and cut it in with a pastry blender or 2 knives until it's the texture of grits or polenta meal with lumps the size of small peas. Do not overblend; small lumps of shortening are what ...