These sweet and savory Portobello Mushroom and Caramelized Onion Sliders will have you wanting more! Portobello mushrooms marinated in balsamic vinegar and Dijon mustard with sweet caramelized onions on your favorite bun, what's not to love!
Portobello mushrooms: Wipe mushrooms with a damp towel and slice into ½ " slices. Mix balsamic vinegar, Dijon mustard, and olive oil. Marinate the mushrooms for at least an hour.
Caramelized onions: Add olive oil to a hot pan. Add sliced onion and cook on medium-low heat for about 35-40 minutes, or until onions are caramelized. Add balsamic vinegar to deglaze the pan. Add salt. Remove onions.
Portobello mushrooms: In the same pan that you cooked the onions, place marinated mushrooms and marinade. Cook on medium heat until mushrooms are tender and marinade is cooked down.
Maple Dijon Mayo: Mix all ingredients.
Slather Maple Dijon Mustard on buns. Add portobello mushrooms and caramelized onions.