Preheat oven to 400 degrees F.
Sift flour, sugar, baking soda and salt together in a large bowl.
In a separate bowl, cream butter.
Add mashed ripe bananas and eggs to butter and mix together.
Add dry ingredients to wet ingredients and mix until well combined.
Mix in oats.
Take a knife and "slice" nutella into batter with a knife. Don't mix it in completely, the stripes are what make them pretty!
Spoon "drops" onto a greased cookie sheet. (Note: this is a lot softer than normal cookie dough and will not form balls, hence spoon “drops”)
Bake at 400 degrees F for about 8-10 minutes.
You can frost these cookies if you would like too! Here is my easy buttercream recipe: 1/2 cup butter-softened, 3 Tbsp. milk, 2 tsp. vanilla, 1 box (16 oz.) powdered sugar. Beat all ingredients together. You can add more milk or powdered sugar to get it to the consistency you want it.