01 - Place strawberries, sugar, and lemon juice in a blender. Process until completely smooth, about 30 seconds.
02 - Add milk, heavy cream, vanilla extract, and ice cubes to the blender. Blend on high speed until fully combined and frothy with a slushy consistency, approximately 45-60 seconds.
03 - Taste the mixture and add additional sugar if needed. Blend briefly to incorporate any adjustments.
04 - Divide the frappuccino evenly between two tall glasses. Top with whipped cream and fresh strawberry slices if desired. Serve immediately while cold.