Stirred Skim Yogurt with Thyme-Garlic Mushrooms

Steps

1. Wash a heavy pot, whisk, thermometer, spoon and a lidded container in hot soapy water, rinse and sanitize them, and let them air-dry.
2. Pour the skim milk into the pot and heat over medium-low, stirring often so it doesn't scorch, until it reaches 180°F (82°C). Hold it at 180°F (82°C) for 10 to 20 minutes, stirring now and then.
3. Take the pot off the heat and cool the milk to 108–112°F (42–44°C), about 30 minutes, or faster with the pot set in a sink of cold water; check with the thermometer.
4. Add the live yogurt starter: stir the plain yogurt into the 108–112°F (42–44°C) milk, whisking gently until smooth.
5. Cover the pot and incubate at 108–112°F (42–44°C) for 6 to 8 hours, such as in an oven with only the light on or wrapped in towels, until the yogurt is set and tangy.
6. Immediately refrigerate the covered pot of set yogurt at 40°F (4°C) or below for at least 4 hours, until cold.
7. Whisk the cold yogurt until smooth and creamy and spoon it into the clean container. The yield is about 1 kg of stirred yogurt, roughly 250 g per serving; keep it refrigerated.
8. When ready to serve, wash the pot, set it over medium-high heat and add the olive oil.
9. Add the mushrooms and cook, stirring occasionally, until browned and their liquid has cooked off, 7 to 8 minutes.
10. Stir in the garlic and thyme and cook for 1 minute, then season with the salt and black pepper and take the pot off the heat.
11. Divide the cold yogurt among 4 bowls, top each with a quarter of the warm mushrooms, and finish with the parsley and lemon zest.