Set Skim Yogurt with Cucumber, Dill and Mint

Steps

1. Wash a heavy pot, whisk, thermometer, small bowl and four 8-ounce jars in hot soapy water, rinse, then sanitize by pouring boiling water over them; let them air-dry.
2. Heat: pour the commercially pasteurized skim milk into the pot and heat over medium-low, stirring often, until it reaches 180°F (82°C). Hold it at 180–185°F (82–85°C) for 15 minutes, stirring now and then, for a firmer set.
3. Cool: take the pot off the heat and cool the milk to 108–112°F (42–44°C), about 30–40 minutes, or set the pot in a sink of cold water to speed it up, checking with the thermometer.
4. Add the starter: once the milk is at 108–112°F (42–44°C), whisk the live-culture plain yogurt in the small bowl with about a ladleful of the warm milk until smooth, then stir this mixture back into the pot.
5. Incubate: pour the cultured milk into the jars. Keep them at 108–112°F (42–44°C) for 6–8 hours, such as in an oven with only the light on or a cooler with warm water, without moving the jars, until set and tangy.
6. Refrigerate: cap the jars and refrigerate immediately at 40°F (4°C) or below for at least 3 hours until cold and firm. The yield is about 4 cups of set yogurt, as nothing is drained.
7. After chilling and shortly before serving, toss the cucumber with the dill, mint, green onion, garlic, lemon juice, salt and black pepper to make the herb topping.
8. Spoon the herb topping over each jar of yogurt, drizzle with the olive oil and scatter the walnuts on top. Keep leftover plain yogurt chilled up to 1 week.