Stirred 2% Yogurt with Vanilla Mango Jam

Steps

1. Wash a heavy pot, whisk, thermometer and a clean 1.5-quart glass jar in hot soapy water, rinse, then pour boiling water over the jar, whisk and thermometer to sanitize; let them air-dry.
2. Heat: pour the commercially pasteurized 2% milk into the pot and heat over medium-low, stirring often so it doesn't scorch, until the thermometer reads 180°F (82°C). Hold it at 180–185°F (82–85°C) for 15 minutes, stirring now and then, for a thicker, creamier yogurt.
3. Cool: take the pot off the heat and cool the milk to 108–112°F (42–44°C), about 30–40 minutes, or faster with the pot set in a sink of cold water; skim off any skin.
4. Add the starter: once the milk is at 108–112°F (42–44°C), whisk the plain yogurt with a ladle of the warm milk in a small bowl until smooth, then stir it back into the pot of milk.
5. Incubate: pour the cultured milk into the sanitized jar, cover, and keep it at 108–112°F (42–44°C) for 6–8 hours, such as in an oven with only the light on (check with the thermometer) or wrapped in towels in a cooler with a jar of hot water, until set and tangy.
6. Refrigerate: immediately move the yogurt to the fridge at 40°F (4°C) or below and chill for at least 2 hours, until cold.
7. While the yogurt chills, rinse and dry the pot, then add the mango, brown sugar and lemon juice and cook over medium heat, stirring, for 8–10 minutes until the mango is soft and jammy.
8. Stir the vanilla and cinnamon into the mango jam, transfer it to a clean container and refrigerate until cold.
9. Toast the walnuts in a dry skillet over medium heat for 3–4 minutes until fragrant, then let them cool.
10. Whisk the cold yogurt for about 30 seconds until silky and stirred-smooth; this makes about 4 cups (no whey is drained).
11. Spoon the yogurt into four bowls, swirl half of the mango jam into the bowls, top with the remaining half of the jam, then scatter the walnuts over each.
12. Keep leftover yogurt covered in the fridge and use within 1–2 weeks; save a few spoonfuls of plain yogurt as the starter for your next batch.