For the yogurt you should use whatever yogurt you like best. We tested this with a couple of different readily available Greek-style yogurts, both nonfat. They both made a beautifully smooth and creamy frozen yogurt.
- Yield:makes about 1 quart
- Active time: 30 minutes
- Total time:4 hours (or overnight)
- 3/4 cup plus 2 tablespoons sugar
- 3/4 cup plus 2 tablespoons water
- 2 Tahitian vanilla beans
- 1 pound blueberries (about 3 1/2 cups)
- 1 tablespoon vanilla extract
- ¼ teaspoon kosher salt
- 3/4 cup plus 2 tablespoons light corn syrup
- 2 pounds Greek yogurt
Bring the sugar, water, vanilla beans (split and scraped) and blueberries to a boil in a saucepan. Turn the heat off as soon as this mixture boils so it doesn’t reduce. Stir in the corn syrup, kosher salt, and vanilla extract.
Cool completely; refrigerate overnight if possible. Refrigerating overnight will allow the blueberries to fully absorb the full flavor of the vanilla beans. (But if you are really craving frozen yogurt right now, it is not a step that is crucial.)
Remove the vanilla beans and add the yogurt. Use a hand blender to blend the mixture until the yogurt is completely emulsified and the blueberries are completely pureed. (Alternately, you can put this into a blender and puree it, but I like the convenience of the hand blender.) The mixture could be passed through a chinois if you’d like something more refined, but we like the rustic chunkiness of the blueberry skins and seeds throughout the frozen yogurt.
Freeze this in your ice cream maker according to manufacturer's directions, keeping this tip in mind: the colder the frozen yogurt base is to begin with, the less time it will take for the ice cream freezer to freeze it. This results in smaller crystals of ice which will lead to a creamier frozen yogurt.