This one-pan dish has flavors reminiscent of the Italian-American classic sausage-and-peppers, but is much lighter. We've swapped the typical sausage for lean and juicy pork tenderloin and added pickled pepperoncini for zip.
Preheat the broiler. Slice the pork on an angle into 1-inch-thick pieces; season with salt. Heat a large ovenproof skillet over medium-high heat; add 1 tablespoon olive oil. Add the onion and bell peppers; season with 1/2 teaspoon salt and cook until the vegetables are crisp-tender and slightly browned, 4 to 6 minutes. Transfer to a plate.
Add the remaining 2 tablespoons oil to the skillet. Add the pork and sear over high heat until browned, 2 to 4 minutes per side. Transfer the pork to the plate with the onion and peppers.
Reduce the heat to medium and add the garlic, sage and tomato paste to the skillet. Cook, stirring, until the tomato paste turns brick-red, about 1 minute. Add the pepperoncini slices and their liquid, then pour in the wine and bring to a boil, scraping up any browned bits with a wooden spoon or spatula. Add the broth and return to a simmer. Arrange the pork in a single layer in the skillet; add the onion and peppers and sprinkle with cheese. Transfer to the oven and broil until the pork is cooked through, 4 to 7 minutes.