Place diced strawberries and sugar in a pot that is 4 quarts or larger. Cook on low, stirring often until the sugar melts.
Turn up the heat and cook the strawberries until you have a thick jam. No need to remove foam but stir every couple minutes and watch so the mixture doesn't boil too hard. In the end you should have about 1-1/2 cups of jam.
If desired, strain jam through a sieve to remove seeds.
Puree 3/4 cup of strawberry jam with lemon juice, yogurt, sea salt and vodka.
Refrigerate the mixture for at least 4 hours. Also place a 4 cup covered container for the finished frozen yogurt in the freezer. Refrigerate leftover jam as well.
Start your ice cream maker and pour in the frozen yogurt base. Using my Cuisinart Gelateria it took about 15 minutes to churn.
Once the strawberry frozen yogurt is fully churned, get out your frozen container. To make strawberry ripples, layer frozen yogurt with strawberry jam.
Freeze strawberry frozen yogurt until firm.
If your ice cream bowl needs to be frozen first, don't forget to put it in the freezer!
The overnight refrigeration of the base prevents ice crystals developing during the freezing process.