Authentic Homemade Yogurt - cooking recipe

Ingredients

3/4 cup plain yogurt, preferably Greek-style, with live cultures
1 quart whole milk
1 quart half-and-half
1 pint heavy whipping cream (optional)

Preparation

On a work surface, lay four clean cotton towels in a cross pattern, each with one end overlapping a few inches in the center. Position a large baking dish or glass mixing bowl in the center of the towels.
Set the plain yogurt on the counter to warm to room temperature while preparing milk mixture.
Combine milk and half-and-half in a large, heavy, non-aluminum pot. Heat over low to moderate heat, stirring constantly, until mixture just comes to the boil. Immediately remove from heat and pour mixture into the waiting bowl. Add 1 pint whipping cream, if desired, for added richness.
Allow mixture to cool to 112 degrees F (44 degrees C). Gradually pour 1 cup of the warm milk into the yogurt, whisking constantly. Return the yogurt-milk mixture to the bowl and stir well. Cover bowl with plastic wrap; wrap kitchen towels up and over bowl, covering completely. Let stand at room temperature until firmly set, 8 to 12 hours.
Refrigerate yogurt several hours or overnight to chill completely.