Place the fresh or frozen berries into your blender first. Then add the simple syrup, margarita mix, orange juice and ice cubes over top.
Start the blender and blend until the ingredients are well combined and have a consistent slushy texture. If the blender gets stuck, add water in ¼ cup increments.
Place sugar on a plate. Rub a lime wedge around the edge of the glass. Roll the rim of the glasses in the sugar to coat.
Split the frozen strawberry margarita between the rimmed glasses.
Garnish with a lime wedge and a fresh strawberry slice.
Notes
Make your own margarita mix: Mix 2 cups lime juice with 2 cups simple syrup (made with 1 cup sugar dissolved in 1 cup water). Make just enough for this recipe: Combine 4 ounces lime juice and 4 ounces simple syrup. No simple syrup? Add 1 cup sugar and 1 cup water to the blender with everything else. Frozen berries: If using frozen berries, you may need to blend everything up longer.