Soak Like You Mean It: Cover the cashews with hot water and let them soak 20 to 30 minutes, then drain. If you’re in a hurry, simmer them 10 minutes, then drain.
Char for Real Flavor: Heat a dry skillet or griddle over medium-high and roast tomatillos, jalapeños, onion slices, and garlic until blistered and browned in spots, turning as needed, about 8 to 12 minutes.
Blend the Green Gold: Blend the roasted salsa ingredients with cilantro, lime juice, and cumin until smooth. Add a splash of water only if needed. Taste and adjust with more lime, and salt if you use it. Set aside.
Prep Your Veg Like a Pro: Slice mushrooms, onions, peppers, and jalapeños. Pat mushrooms dry so they brown instead of steam.
Brown the Mushrooms First: Heat a large skillet over medium-high, add 1 tbsp oil, then add mushrooms in a single layer. Let them sit 2 to 3 minutes untouched, then stir and cook 5 to 7 minutes until most moisture cooks off and you see browned edges.
Bring in the Fajita Crew: Add the remaining 1 tbsp oil, then add onions, peppers, and sliced jalapeños. Cook 6 to 8 minutes until softened but still a little crisp.
Garlic at the Right Time: Add minced garlic and cook 60 seconds, just until fragrant.
Toast the Spices: Sprinkle in smoked paprika, cumin, oregano, chili powder, black pepper, and salt if using, then stir and cook 1 minute so the pan smells amazing.
Do the Dry-Out Move: Spread the filling into an even layer and let it sit 1 to 2 minutes without stirring. Stir and spread again. Repeat once more. This is how you get crisp quesadillas that slice clean.
Finish Bright: Turn off the heat and stir in lime juice. Let the filling cool 5 minutes so your tortillas stay crisp.
Mash the Avocado Seal: Mash avocados with lime juice and salt if using. Keep it thick, not runny.
Blend the Cashew Queso: Blend drained cashews with water, nutritional yeast, lemon juice, seasonings, and salt if using until silky smooth. Add water 1 tbsp at a time until it dips nicely. Warm it on low 2 to 3 minutes if you want it extra queso-like.
Warm the Tortillas: Warm each cassava tortilla in a dry skillet 15 to 20 seconds per side so it bends without cracking.
Build the Fajita Fold: Spread a thin layer of avocado on one half of each tortilla, add a single layer of filling (do not overstuff), leave a 1/2 inch border, then fold and press gently.
Crisp to Golden: Cook quesadillas over medium heat 2 to 4 minutes per side, pressing gently with a spatula so they brown evenly. If they brown too fast, lower the heat and cook a little longer.
Rest Then Slice: Let each quesadilla rest 1 minute, then slice into wedges. Serve with salsa verde and cashew queso dip on the side, plus guac if you want to be extra.