Vanilla Frozen Yogurt

Fill a large bowl halfway with ice water, and set aside. Combine sugar, lemon juice, 3 tablespoons water, and salt in a saucepan. Using the tip of a paring knife, scrape seeds from vanilla bean into pan, and discard pod. Bring to a boil, and cook, stirring, until sugar has dissolved.

Whisk yolks in a large bowl. Pour in hot sugar syrup in a slow, steady stream, whisking until combined. Whisk in corn syrup, followed by the yogurt and then the cream. Pour through a fine sieve into a bowl, and place bowl in ice bath. Let stand, whisking occasionally, until thoroughly chilled, about 15 minutes.

Freeze mixture in an ice cream maker according to manufacturer's directions. Transfer to a container, and press plastic wrap on surface. Freeze for at least 30 minutes before serving. If freezing longer than 30 minutes, let stand at room temperature until slightly softened.