Preheat oven to 375°.
Heat a Dutch oven or oven-safe, heavy-bottomed pot over medium-high heat with 2 tablespoons of EVOO, about 2 turns of the pan. Add the chopped bacon and cook until browned. When it is crisp and brown, remove the bacon from the pan to a paper towel lined-plate and reserve.
Season the chopped sirloin with salt and freshly ground black pepper, and add 1/3 of it to the bacon fat in the pan. Cook the meat, stirring occasionally, until deep golden brown, about 10 minutes. Remove the seared meat to a plate and cook the remaining 2/3 of the meat in two batches, adding more EVOO to the pan if necessary.
With all the meat out of the pan, add the wine and scrape up any brown bits from the bottom of the pan. Bring the wine to a bubble and reduce slightly. Add the beef stock, reserved meat and bacon back to the pot, then cover the pot and transfer it to the oven. Bake 90 minutes.
After the meat has been baking for 60 minutes, place a small, sauté pan over medium-high heat with the onions, sugar and a splash of water. Cook until the water has evaporated and the onions are tender and heated through, 4-5 minutes. Reserve and keep warm.
While the onions are cooking, place a medium-size skillet over medium-high heat with 1 tablespoon butter and 1 tablespoon EVOO, 1 turn of the pan. Cook the mushrooms until tender and golden brown, about 10 minutes, then season with salt and freshly ground black pepper. Reserve and keep warm.
Place a large pot of water over high heat to cook the noodles. Once boiling, add some salt and the noodles and cook to al dente, according to package directions. Drain and return them back to the pot. Add 2 tablespoons of butter and the minced chives, toss to combine.
Once the meat has finished cooking, remove the pot from the oven and place it over medium-high heat. Add the cooked vegetables to the pot and bring it up to a bubble. Place the pan the mushrooms were cooked in over medium-high heat and melt 2 tablespoons butter. Sprinkle the flour over the butter and cook the mixture for about 1 minute. Add about 1 cup of the liquid from the Dutch oven (eyeball it) to the roux and whisk them to combine. Bring the sauce up to a bubble to thicken it, and then add it to the ingredients in the Dutch oven. Simmer the stew in the Dutch oven until thickened, 5-6 minutes.
To serve, stir the orange zest into the stew and ladle it up over the buttered noodles.