Thick-Set Skim Yogurt with Pear and Walnuts

Steps

1. Wash a heavy pot, a whisk, a ladle, a small bowl, four 1-cup (250 ml) jars with lids and a thermometer in hot soapy water, rinse, then sanitize by pouring boiling water over them; let air-dry.
2. Pour the commercially pasteurized skim milk into the pot and heat over medium-low, stirring often so it doesn't scorch, until it reaches 180°F (82°C).
3. Hold the skim milk at 180–185°F (82–85°C) for 20 minutes, stirring now and then; this longer hold firms the set of a low-fat yogurt.
4. Take the pot off the heat and cool the skim milk to 108–112°F (42–44°C), setting the pot in a sink of cold water and stirring to speed it up, about 15 minutes.
5. In the small bowl, whisk the plain yogurt with a ladleful of the warm milk until smooth, then whisk this starter mixture back into the pot.
6. Ladle the cultured milk into the sanitized jars and cover. Incubate undisturbed at 108–112°F (42–44°C), in an oven with only the light on or an insulated cooler with warm-water jars, for 6–8 hours, until set firm and it pulls cleanly from the jar side when tilted.
7. Refrigerate the jars right away at 40°F (4°C) or below for at least 3 hours to chill and firm further. Yield is about 1 kg (four 1-cup jars); nothing is drained, so the nutrition matches the starting ingredients.
8. While the yogurt chills, toast the walnuts in a dry skillet over medium heat for 3–4 minutes until fragrant, then cool.
9. Toss the pear with the maple syrup and the cardamom.
10. To serve, spoon the pear mixture over each jar of chilled yogurt and scatter the toasted walnuts on top.