Preheat oven to 350°F and spray ramekin with cooking spray.
Place oats in blender and blend for 30 seconds, or until oats reach a fine powder consistency.
Add remaining ingredients (excluding hazelnuts) and blend another 30 seconds until smooth.
Pour into prepared ramekin. Add another spoonful of Nutella on top and sprinkle on chopped hazelnuts.
Bake in preheated oven for 25-30 minutes and enjoy warm.
Vegan Option: You'll just have to make a few substitutions to make these Nutella baked oats vegan! First, Nutella itself contains milk, so you can use a vegan hazelnut spread instead. Then, just substitute plant milk, use maple syrup as your sweetener, and swap in a vegan egg!Microwave Option: If you like, you can make these Nutella baked oats in the microwave in just 2 minutes! Heat the ramekin on high for 1½ - 2½ minutes, checking after 2 minutes.