Simple Swedish Chocolate Oat Balls (Chokladbollar)

Name: Simple Swedish Chocolate Oat Balls (Chokladbollar)
Prep time: 10 min
Total time: 10 min
Cuisine: European
Ingredients: 150g (⅔ cup) butter (room temperature); 180g (⅞ cup) sugar; 1½ tsp vanilla sugar (see note 1); 40g (⅜ cup) cocoa; 3 tbsp cold strong brewed coffee (see note 2); 280g (3 cups) oats; coconut, pearl sugar or sprinkles (use as much as needed to cover the balls)