I'm a sucker for homemade frappacino.
Instant coffee (I usually use decaf)
Stevia (make sure it's allergen free) or sweetener of your choice
Milk of your choice (we use coconut milk)
Put all these in the blender. Blend.
Add ice, blend until smooth. I have a Vitamix and I love it an insane amount.
Play around with the amounts of everything until you find something you like. I like to sometimes add some homemade chocolate sauce, vanilla or mint extract to create different tastes. It satisfies my sweet tooth for minimal calories.