Blackberry Ice Cream
4 cups fresh blackberries
1 1/3 cups sugar
1/2 cup water
1 vanilla bean, split and scraped
2 cups milk
6 large egg yolks
2 cups heavy cream
Combine 3 cups blackberries with 1 cup sugar and the water in a medium nonreactive saucepan. Bring to a oil over medium heat. Reduce heat to a simmer and cook, stirring constantly until sugar dissolves and berries begin to fall apart, about 4 minutes.
Remove from heat. Pass berry mixture through a fine sieve into a medium bowl, gently pressing down on the solids with a wooden spoon to release as much liquid as possible. Measure out 1/2 cup solids, and set aside; discard remaining solids. Measure out 1 2/3 cups strained puree and return it to saucepan; reserve any remaining puree for serving.
Place vanilla bean and scrapings in a saucepan and add milk. Bring to a gentla boil over medium heat, and remove from heat. Discard vanilla pod.
Prepare an ice bath, and set aside. Combine egg yolks and the remaining 1/3 cup sugar in the bowl of an electric mixer fitted with the whisk attachment. Bean on medium high speed until mixture is pale yellow, 3-5 minutes.
Using a measuring cup or ladle, slowly pour about 1/2 cup hot milk mixture into the egg yolk mixture, beating constantly on low speed until blended. Continue adding milk mixture, about 1/2 cup at a time, beating until thoroughly combined after each addition.
Return mixture to saucepan. Cook over medium heat, stirring constantly with a wooden spoon until thick enough to coat the back of the spoon and hold a line when drawn across the back of the spoon with you finger, 6-8 minutes.
Remove from heat; add reserved strained puree and immediately stire in the cream to stop the cooking. Pour through a fine sieve into a medium bowl set in the ice bath; let cool completely, stirring occasionally. Cover bowl with plastic wrap and place in the refrigerator until thoroughly chilled, at least 30 minutes or overnight.
Freeze mixture in an ice cream maker according to manufacturer's instructions; it should still be slighly soft. Stir in the reserved 1/2 cup blackberry solids and remaining 1 cup blackberries; spin a few times in ice cream maker to distribut evenly. Transfer mixture to an airtight container and place in the freezer until ice cream is completely set, at least 4 hours and up to 1 week.