Adjust a rack to the lower middle (but not the bottom) of the oven and heat the oven to 450°F.
Pat the beef dry with paper towels, trim away any thick pieces of fat, and cut into 1-inch cubes. Season generously with salt and pepper. Heat 2 Tbs. of the oil over medium-high heat in a heavy-based Dutch oven that’s 9 to 10 inches in diameter. As soon as the oil is very hot, add a quarter of the beef cubes, taking care not to crowd the pan. Sear the beef until two sides form an impressive dark-brown crust, 8 to 10 minutes. Transfer the beef to a bowl and continue to sear the remaining beef in batches, adding more oil to the pan if needed. It’s fine for the pan bottom to darken, but if it smells like it’s burning, lower the heat just a little. Set all the seared beef aside in a bowl.
Reduce the heat to medium and add the onions and garlic to the empty pot, adding another 1 Tbs. oil if the pan is dry. Cook, stirring frequently, until soft, about 5 minutes.
Add the chili powder, cumin, and oregano, and continue to cook, stirring, until fragrant, 30 seconds to a minute. Season with salt and pepper. Stir in the flour and then the tomatoes with their juices, the white wine, and 1 cup water. Return the beef and any accumulated juices back into the pot.
Lay a large sheet of heavy-duty foil over the pot and, using a potholder or a thick towel, press it down in the center so that it almost touches the stew. Crimp the foil around the pot’s rim for a tight seal. Cover snugly with the pot’s lid. Turn the burner to medium high until you hear the juices bubble. Put the pot in the oven and cook for 1 hour and 15 minutes. Check the stew: If the meat is fork-tender, it’s done; if not, cook for another 15 minutes, adding a little more water to the pan if it looks dry.
Meanwhile, heat a large sauté pan over medium- high heat. Add enough oil to cover the bottom of the pan and sauté the squash and red and green bell pepper until just tender and lightly browned. Remove from the heat and set aside.
Remove the pot from the oven, carefully remove the foil, and stir in the cooked vegetables and the pinto beans. Remembering that the pot and lid are hot, cover again with the foil and the lid. Let stand so that the meat rests and the vegetables marry, about 15 minutes.
When ready to serve, the stew juices might need thinning to achieve a thin gravy texture. If so, stir in water—1/4 cup at a time—as needed. Season with salt and pepper to taste. Gently reheat, if necessary, and serve garnished with the cilantro.