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Mushroom Sloppy Joes

Helen T. Patterson
A flavorful vegetarian twist on classic sloppy joes, featuring a savory mushroom and walnut filling, smoky spices, and a crunchy slaw,
served with a zesty chipotle aioli. High in plant-based protein, fiber, and healthy fats, this quick, 40-minute recipe is perfect for weeknight dinners or meal prep.
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Prep Time 10 minutes
Cook Time 30 minutes
Total Time 40 minutes
Course Main Course, Sandwich
Cuisine American, Vegetarian
Servings 4 (sandwiches)

Equipment

  • 1 Large skillet
  • 1 Medium Bowl
  • 1 small bowl
  • 1 spatula
  • 1 knife
  • 1 cutting board
  • Measuring Cups and Spoons

Ingredients
  

Mushroom Sloppy Joes Filling

  • 1 tablespoon oil
  • 2 medium onions minced
  • 1 lb crimini or button mushrooms finely chopped
  • 3 cloves garlic minced
  • ½ cup tomato paste or one 5.5-ounce can
  • 1 bottle light beer preferably lager
  • 1 cup walnuts chopped
  • 2 tablespoons Worcestershire sauce vegan optional
  • 2 tablespoons chipotle peppers in adobo sauce
  • 2 teaspoons chili powder
  • 1 teaspoon sea salt
  • 4 hamburger buns

Slaw

  • 2 cups purple cabbage shredded
  • 1 medium carrot grated
  • ¼ cup red onion thinly sliced
  • A handful fresh cilantro chopped
  • Olive oil for drizzling

Chipotle Aioli

  • ¼ cup mayonnaise vegan optional
  • 1 tablespoon chipotle peppers in adobo sauce
  • Juice of ¼ lime
  • Pinch of sea salt

Instructions
 

  • Heat the Pan and Sauté Onions: Start by heating 1 tablespoon of oil in a large skillet over medium heat.
    Once the oil shimmers, add the minced onions.
    Cook them slowly, stirring occasionally, until they turn a deep golden brown and release a natural sweetness.
    This process should take about 10 minutes. Browning the onions gradually is key to building rich, savory flavor for the filling.
  • Cook the Mushrooms to Perfection: Add the finely chopped mushrooms to the skillet with the onions.
    Increase the heat to medium-high so the mushrooms release their moisture and then begin to evaporate it.
    Stir occasionally to ensure even cooking.
    Continue until the pan is mostly dry and the mushrooms have browned beautifully, which usually takes around 10 minutes.
    This step concentrates their flavor and prevents a soggy filling.
  • Incorporate Garlic for Aroma: Reduce the heat back to medium and stir in the minced garlic.
    Cook for an additional 5 minutes, allowing the garlic to mingle with the onions and mushrooms.
    You’ll notice a fragrant, savory aroma—this step ensures the garlic flavor infuses the entire filling without burning.
  • Prepare the Slaw While Cooking: While the mushrooms are cooking, make the slaw. In a medium bowl, combine 2 cups shredded purple cabbage, 1 grated carrot, ¼ cup thinly sliced red onion, and a handful of chopped cilantro.
    Drizzle lightly with olive oil and toss gently to coat.
    Set aside. The slaw will add a crisp, refreshing crunch that balances the warm, savory filling.
  • Mix the Chipotle Aioli: In a small bowl, whisk together ¼ cup mayonnaise, 1 tablespoon chipotle peppers in adobo sauce, juice of ¼ lime, and a pinch of sea salt.
    Taste and adjust seasoning as needed. The chipotle aioli provides a smoky, creamy kick that complements the mushrooms and slaw perfectly.
  • Caramelize the Tomato Paste: Push the mushroom mixture to one side of the skillet. Add ½ cup tomato paste to the empty space and stir occasionally.
    Let it cook for about 3 minutes, allowing it to caramelize slightly and deepen in flavor.
    This step adds natural sweetness and richness, which is essential for the classic sloppy joe taste.
  • Deglaze with Beer: Pour in 1 bottle of light beer (lager works best) and scrape any browned bits from the bottom of the skillet with a spatula.
    These caramelized bits carry concentrated flavor that will enrich the sauce. Stir well to incorporate the tomato paste and beer fully.
  • Add Walnuts and Spices: Add 1 cup chopped walnuts, 2 tablespoons Worcestershire sauce, 2 tablespoons chipotle peppers in adobo sauce, 2 teaspoons chili powder, and 1 teaspoon sea salt to the skillet.
    Stir thoroughly to combine all ingredients.
    Taste and adjust salt or spice levels as needed.
    The walnuts add a satisfying crunch and plant-based protein, while the spices provide the signature smoky heat.
  • Toast the Buns (Optional but Recommended): While the filling simmers, slice 4 hamburger buns in half.
    Lightly toast them in a dry skillet, oven, or toaster for 2–3 minutes until golden.
    Toasting adds texture, prevents sogginess, and enhances the overall eating experience.
  • Assemble the Mushroom Sloppy Joes: Spoon the hot mushroom and walnut mixture generously onto the bottom half of each toasted bun.
    Top with a layer of the prepared slaw, then drizzle with the chipotle aioli. Place the top bun on each sandwich and press gently.
    The combination of warm filling, crunchy slaw, and creamy aioli creates a perfect balance of textures and flavors.
  • Serve and Enjoy: Transfer the assembled sandwiches to a serving plate. These
    Mushroom Sloppy Joes are best enjoyed immediately while warm, though they also store well for later.
    Serve with a side salad, sweet potato fries, or simply on their own for a satisfying meal that’s both hearty and nutritious.

Notes

  • Versatile and forgiving recipe, perfect for both beginner and experienced cooks.
  • Finely chopped mushrooms create a meaty texture that mimics traditional sloppy joes.
  • Toasting the buns prevents sogginess from the saucy filling.
  • Walnuts add protein, healthy fats, and a satisfying crunch.
  • Chipotle aioli can be prepared ahead of time to save assembly time.
  • Slaw provides a crisp, refreshing contrast to the warm, smoky filling.
  • Adjust the spice level by adding more or fewer chipotle peppers in adobo sauce.