Add the frozen strawberries, agave nectar (or honey), yogurt and lemon juice to the bowl of a food processor. Process until creamy, about 5 minutes.
Serve the frozen yogurt immediately or transfer it to an airtight container and store it in the freezer for up to 1 month.
Note: Skip the sugary store-bought desserts and whip up the best healthy strawberry frozen yogurt made with just four ingredients. No ice cream maker required!