4 cups whole milk plain yogurt
¾ C sugar
½ C cocoa powder
1 C milk
½ tsp vanilla
optional: 1 C chocolate chips (semi-sweet or white), chocolate covered pretzels, candy bar pieces, etc.
Strain the yogurt: Using cheese cloth (or heavy duty paper towels lining a collander) strain yogurt for about 2 hours. This removes excess liquid to prevent frozen yogurt from being too runny.
In a large bowl thoroughly mix strained yogurt, sugar, cocoa powder, salt, milk and vanilla. Whisk until sugar is dissolved. Cover and place in freezer for 2-3 hours.
Pour mixture into ice cream maker and mix until thickened (about 15-20 minutes). When frozen yogurt is almost done churning, add chocolate chips, pretzels, candy pieces or other 'stir ins'.
Frozen yogurt will be soft and creamy. For a firmer consistency, place in freezer for another 2+ hours.