Cheesy Portobello Mushroom Sliders

Cheesy Portobello Mushroom Sliders

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Meaty portobello mushroom sliders with savory caramelized onions and smothered in Core and Rind rich and smoky dairy free cheese sauce. Serve on your favorite bun for a game day appetizer or weeknight dinner. They are cheesy lick-your-fingers-clean delicious! 


Caramelized Onions

2 cups sliced onions (sweet or white)

2 Tbsp olive oil


Splash of red wine vinegar


4 small portobello mushrooms
¼  cup red wine vinegar

½ Tbsp soy sauce (liquid aminos)

½ Tbsp maple syrup

1 tsp steak seasoning


¼-⅓ cup Core and Rind Rich and Smoky

Slider buns (gluten free if needed)

Toppings: chopped parsley, tomato, lettuce, vegan mayo


  1. Slice onion into thin slices. Heat oil in a skillet over medium-high heat. When oil is hot, add onions, sprinkle with a pinch of salt and reduce heat to medium-low. Cook, stirring occasionally for 30 minutes. Onions are ready when they start to turn brown and slightly charred in appearance. Be patient! If they start to burn too early add a splash of water and continue until all mushrooms start to brown. 
  2. While onions are cooking, wipe mushrooms clean with a damp cloth and carefully remove stems. Place in a shallow bowl or reusable marinade bag. 
  3. Place red wine vinegar, soy sauce, maple syrup and steak seasoning in a small bowl and whisk to combine. Pour marinade over mushrooms. 
  4. When onions are done, remove from skillet to a plate to rest. Quickly deglaze skillet with a splash of red wine vinegar. 
  5. Add mushrooms and marinade to skillet over low heat. Cook mushrooms on each side for approximately 3 minutes. Time will vary depending on how large your mushrooms are in size. If the marinade dries up, add a splash of water to deglaze the pan. 
  6. Turn off heat when mushrooms are tender. Fill each cup with generous amounts of Core and Rind Rich and Smoky cheesy sauce. 
  7. Serve with slider buns and optional toppings. 

What buns should I use? 

Any dinner sized roll or slider bun works!
For vegan and gluten free, I used Bread Seriously sourdough dinner rolls

What size mushrooms should I use?
For this recipe I used small baby portobello mushrooms. They are slightly smaller than the larger sized portobellos. If you can’t find them, you can use 2 larger portobello mushrooms, you may need a larger bun or you can slice the larger ones in half. 

How do I know when my mushrooms are ready? 

They will be darker around the edges and will have released some liquid. 

Can I use other flavors of cheese sauce? 

Yes! For this recipe, sharp and tangy would be delicious, too! 

What other sliders can I make with Core and Rind cheesy sauce?

You could make an eggplant slider, zucchini or use your favorite veggie burger! Our red lentil cheeseburger cup filling would be amazing as well. 

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