Vegan Patty Melt with Caramelized Onions

This vegan patty melt takes everything you love about the classic diner sandwich and makes it entirely plant-based without sacrificing an ounce of indulgence. A hearty black bean and mushroom patty gets seared until deeply golden, then piled high with slow-cooked, jammy caramelized onions and a stretchy, tangy cashew cheese sauce. The whole stack is sandwiched between slices of rye bread that are slathered in vegan butter and griddled until the crust is shatteringly crisp and the inside is warm and melty. Caramelizing the onions low and slow is the secret to this sandwich's depth of flavor, so don't rush that step — a splash of vegan Worcestershire or tamari and a pinch of sugar help them along to a deep amber sweetness. The cashew cheese sauce, blended smooth with nutritional yeast and a touch of miso, melts beautifully under the heat of the griddle, giving you that classic gooey patty melt pull in every bite. Perfect for a cozy weeknight dinner, this sandwich proves that comfort food can be completely dairy-free and meat-free while still being rich, savory, and utterly satisfying. Serve it with a side of crispy fries or a simple green salad to round out the meal.

Ingredients

• 3 largeYellow onions, thinly sliced
• 6 tbspVegan butter, divided
• 1 tspbrown sugar
• 1 tbspTamari or soy sauce
• 1.5 cupsCanned black beans, drained, rinsed
• 1 cupcremini mushrooms, finely chopped
• 0.5 cupwalnuts, finely chopped
• 0.5 cuprolled oats
• 3 clovesgarlic, minced
• 1 tspsmoked paprika
• 1 tsponion powder
• 1 tspsalt, plus more to taste
• 0.5 tspblack pepper
• 2 tbspolive oil, for sautéing and searing
• 1 cupraw cashews, soaked in hot water 15 minutes, drained
• 3 tbspnutritional yeast
• 1 tbspWhite miso paste
• 1 tbsplemon juice
• 0.5 cupwater, plus more as needed for cheese sauce
• 8 slicesRye bread
• 2 tbspVegan Dijon mustard, optional, for spreading

Method

1. Heat 2 tablespoons of vegan butter in the large skillet over medium-low heat. Add the sliced onions and cook, stirring occasionally, for 25-30 minutes until deeply golden and soft. 30:00
2. Stir in the brown sugar and tamari, then continue cooking for another 5 minutes until the onions are jammy and deeply caramelized. Remove from heat and set aside. 5:00
3. While the onions cook, make the cashew cheese: combine the soaked cashews, nutritional yeast, miso paste, lemon juice, and water in the blender. Blend until completely smooth and creamy, adding more water as needed to reach a thick, spreadable consistency.
4. Pour the cashew cheese into the small saucepan and warm over low heat, stirring frequently, until thickened slightly and melty. Set aside, keeping warm. 5:00
5. In the food processor, pulse the black beans, mushrooms, walnuts, oats, garlic, smoked paprika, onion powder, salt, and pepper until the mixture is combined but still has some texture, not fully smooth.
6. Transfer the mixture to the mixing bowl and shape into 4 equal patties, pressing firmly so they hold together.
7. Heat the olive oil in the griddle over medium heat. Sear the patties for 4-5 minutes per side until deeply browned and firm. Remove and set aside. 10:00
8. Spread vegan butter on one side of each slice of rye bread. On the unbuttered side of 4 slices, spread a thin layer of mustard if using, then top with a patty, a generous spoonful of caramelized onions, and a layer of warm cashew cheese.
9. Top each sandwich with the remaining bread slices, buttered side facing out. Place sandwiches on the griddle over medium heat and cook for 3-4 minutes per side, pressing gently with the spatula, until golden brown and crisp and the cheese is melted inside. 8:00
10. Slice the sandwiches in half and serve immediately while hot and crisp.