Vanilla Frozen Yogurt

1. Place yogurt in fine-mesh strainer set over liquid measuring cup and refrigerate; let drain until yogurt releases 1⁄2 cup liquid, 1 to 2 hours.
2. Sprinkle gelatin over 1⁄4 cup milk in small bowl and let sit until gelatin softens, about 5 minutes.
3. Meanwhile, cut vanilla bean in half lengthwise. Using tip of paring knife, scrape out seeds. Combine vanilla bean and seeds, remaining 1-1⁄2 cups milk, and sugar in small saucepan and heat over medium-high heat, stirring occasionally, until mixture is steaming and sugar is dissolved. Remove pan from heat.
4. Add softened gelatin to hot milk mixture, stirring until completely dissolved. Remove and discard vanilla bean. Let mixture cool to room temperature over bowl of ice water, then combine with drained yogurt. Cover and refrigerate until mixture registers 40 degrees, at least 3 hours or up to 24 hours.
5. Transfer yogurt to ice-cream machine and churn until frozen. Transfer frozen yogurt to airtight container, press firmly to remove any air pockets, and freeze until firm, at least 2 hours.

The frozen yogurt will be soft at the end of churning, but it can be served this way, or it can be chilled until firm. If using a canister-style ice-cream machine, be sure to freeze the empty canister at least 24 hours and preferably 48 hours before churning. For self-refrigerating ice-cream machines, prechill the canister by running the machine for 5 to 10 minutes before pouring in the yogurt. Though the frozen yogurt will keep in the freezer for up to 2 days, its flavor and texture are best when it is eaten the day it is made.

CHOCOLATE FROZEN YOGURT
Omit vanilla bean. Increase sugar to 1 cup and add 6 tablespoons Dutch-processed cocoa to milk along with sugar. Stir in 1 teaspoon vanilla extract after milk mixture cools to room temperature in step 4.

COFFEE FROZEN YOGURT
If you prefer to use fresh coffee, steep 3 tablespoons coarsely ground coffee in the hot milk-sugar mixture until strongly flavored, about 20 minutes. Strain and discard the ground coffee and reheat the mixture before adding the gelatin.
Omit vanilla bean. Increase sugar to 1 cup and whisk 6 to 7 teaspoons instant espresso powder into hot milk mixture. Stir in 1 teaspoon vanilla extract after milk mixture cools to room temperature in step 4.