Homemade Buttermilk (4 servings) 1 cup whole milk either 1 and 3/4 Tablespoons cream of tartar or 1 Tablespoon white vinegar or 1 Tablespoon lemon juice Add acidic ingredient (tartar, vinegar or lemon juice) to the milk and stir. Let stand at room temperature for 15 minutes. The milk should start to curdle. Stir well before using. A combination of plain yogurt (3/4 cup) and whole milk (1/4) cup can also be used to replace a cup of buttermilk in most recipes. You don't have buttermilk, but you're desperate for homemade buttermilk pancakes or biscuits. What are you gonna do? Here's four easy solutions. Mr Breakfast would like to thank Mr Breakfast for this recipe. Recipe number 1192. Submitted 2/23/2004.