Guajillo Fish Tacos

Place an oven rack in the center of the oven, then preheat to 450°F. Wash and dry the fresh produce. Cut the potatoes into 1/2-inch rounds. Halve, peel, and thinly slice the onion. Thinly slice the scallions, separating the white bottoms and hollow green tops. Roughly chop the piquante peppers. Grate the cheese on the large side of a box grater. Cut off and discard the stems of the poblano peppers. Halve lengthwise; remove the ribs and seeds, then thinly slice crosswise. Thoroughly wash your hands, knife, and cutting board immediately after handling. In a bowl, whisk together the guajillo chile sauce and sour cream. Season with salt and pepper. 

Place the potato rounds on a sheet pan; drizzle with olive oil and season with salt and pepper. Toss to coat and arrange in an even layer. Roast 20 to 22 minutes, or until browned and tender when pierced with a fork. Leaving the oven on, remove from the oven. Evenly top with the grated cheese. Return to the oven and roast 2 to 4 minutes, or until the cheese is melted. Remove from the oven. 

Meanwhile, in a large pan (nonstick, if you have one), heat a drizzle of olive oil on medium-high until hot. Add the sliced onion, sliced white bottoms of the scallions, and sliced poblano peppers; season with salt and pepper. Cook, stirring occasionally, 6 to 7 minutes, or until softened. Transfer to a bowl; stir in the chopped piquante peppers. Taste, then season with salt and pepper if desired. Cover with foil to keep warm. Wipe out the pan. 

Pat the fish dry with paper towels; season on both sides with salt, pepper, and enough of the spice blend to coat (you may have extra). In the same pan, heat a drizzle of olive oil on medium-high until hot. Add the seasoned fish. Cook 3 to 4 minutes per side, or until browned and cooked through.* Transfer to a cutting board; carefully halve each fillet lengthwise. 

* An instant-read thermometer should register 145°F.

If you prefer to use a microwave, wrap the tortillas in a damp paper towel and microwave on high 1 minute, or until heated through. If you prefer to use the oven, wrap the tortillas in foil and place directly onto an oven rack; warm 7 to 9 minutes, or until heated through. Transfer the warmed tortillas to a work surface and carefully unwrap. Assemble the tacos using the warmed tortillas, halved fish, finished vegetables, and guajillo sour cream. Serve the tacos with the cheesy potatoes on the side. Garnish the potatoes with the sliced green tops of the scallions. Enjoy!