1
["Preheat broiler. Arrange chiles in a single layer on a rimmed baking sheet. Broil, turning once, until blackened in spots, about 15 minutes. Transfer chiles to a large bowl, cover with plastic wrap, and let steam 15 minutes. Peel, seed, devein, and thinly slice chiles lengthwise.", "Meanwhile, prepare a grill or grill pan for medium-high heat. Grill corn, turning occasionally, until kernels are tender and charred in spots, 15-20 minutes. Let cool, then cut kernels off cob.", "Heat oil in a large skillet over medium. Add onion and cook, stirring occasionally, until light golden and tender, 10-12 minutes. Reduce heat to low, add chiles, corn, and 1 tsp. salt, and cook, stirring occasionally, until warmed through, about 2 minutes. Stir in crema and just heat through (do not bring to boil)-vegetables should be just coated; add more crema if needed. Season with salt.", "If frying tortillas, fit a large skillet with candy or deep-fry thermometer; pour in oil to measure 1"". Heat over medium-high until thermometer registers 375u00b0F. Fry tortillas in batches until crispy, turning every 30 seconds, about 2 minutes total. Drain on paper towel-lined baking sheets and season with salt.", "Spread 1 Tbsp. Creamy Black Bean Spread, if using, on a tostada shell. Top with 1/4 cup rajas, then lettuce, onion, queso fresco, and cilantro. Repeat with remaining tostada shells. Serve at room temperature.", "Rajas can be chilled for up to 1 day. Reheat and let cool to room temperature before serving."]
