|Low fat milk||1 Quart|
|Nonfat dry milk powder||1⁄3 Cup (5.33 tbs)|
|Plain yogurt with active cultures||1⁄4 Cup (4 tbs)|
1. Preheat oven to 275° F.
2. Mix low-fat and dry milk together. Heat to 180° F. Cool to 110° F.
3. Mix a little of the warm milk into yogurt; stir into bulk of warm milk. Pour into clean casserole dish. Cover.
4. Turn oven off. Put yogurt mixture in oven. Let sit, undisturbed, for 4 to 8 hours. The longer it sits, the tarter it will be.
5. Remove from oven. Divide into 1-cup (8-ounce) serving portions, using glass, plastic, or waxed paper containers with covers (or seal with foil, Saran, or waxed paper lids). Refrigerate.