It turned out MEGA delicious, and it tasted just like a dessert! Here is my recipe. I'll also give you the tip to make extra thick "milk foam" with oat drink!
Whisk instant coffee, sugar, and boiling water together in a cup. I used an electric whisk.
Keep whisking until it becomes light, creamy, and airy. This takes about 30 seconds.
Put ice cubes in a glass, shake the carton of oat milk well (this creates more foam) and pour it over the ice cubes.
Scrape the thick coffee foam out of the cup and place it on top of the oat milk. Serve with a straw and stir the glass before drinking the coffee. If you give the oat milk a spin in a "shaker" first, you get EVEN more foam.