I picked the bug up early from daycare, and we made blackberry frozen yogurt from my mom's old recipe. She used to make it every July in Georgia and Virginia. Next time I'll strain out the seeds. (I like the seeds, but others don't.)
Blackberry Frozen Yogurt
4 cups blackberries
2¼ cups sugar
3 large eggs, separated
4 teaspoons fresh lemon juice
4 teaspoons vanilla extract
¼ teaspoon salt
¼ teaspoon cream of tartar
2 quarts plain yogurt
Put the blackberries and 2 cups of the sugar in a small saucepan; bring to a boil and cook, stirring, until the sugar is dissolved and the berries are broken down a bit.
In a large bowl, beat the egg yolks. Stir in ½ cup of the blackberry mixture, then stir in the remaining blackberry mixture, the lemon juice, and vanilla. Set the bowl in another bowl of ice water and let cool to room temperature, stirring frequently. Chill in the refrigerator for at least 4 hours.
Beat the egg whites, salt, and cream of tartar until soft peaks form. Add the remaining ¼ cup sugar and beat until stiff peaks form.
In a large bowl, whisk the yogurt, then fold in the blackberry mixture, then fold the yogurt mixture into the egg whites.
Freeze in an ice cream maker until it's the consistency of runny soft-serve ice cream, then transfer to the freezer until completely frozen.