Warm a stainless steel or cast iron skillet over medium-high heat. Add the bacon and cook until the fat has rendered and the bacon is golden and crispy. Remove the pan from heat and transfer the bacon to a plate lined with a paper towel to drain. Pour off all but a tablespoon of bacon fat from the pan.

Return the pan to medium-high to high heat. Pat the beef cubes dry and sprinkle them with salt and pepper. When the bacon fat is shimmering and you see a wisp or two of smoke, add a single layer of beef cubes to the pan to sear — do not crowd the pan; sear the meat in batches. Let the beef sear without moving until it releases easily from the pan and the underside is golden-brown, 1 to 3 minutes. Flip the pieces and sear on the other side. Again, let the meat sear without moving for 1 to 3 minutes until they release easily from the pan.

Transfer the seared meat to your slow cooker or a clean bowl. Deglaze the pan with 1/4 cup of the wine. Scrape the dark glaze and any crispy bits from the bottom of the pan as the wine simmers. When the pan is clean, pour the wine over the seared meat.

Add 1 tablespoon of leftover bacon grease to the pan. Continue to sear the meat in batches, deglazing the pan between each batch.

When all the meat is seared, add another tablespoon of bacon grease to the pan and reduce the heat to medium. Cook the onions with 1/4 teaspoon of salt until soft and browned, 6 to 8 minutes. Add the carrots and celery, and cook until softened. Add the garlic and tomato paste, and cook until fragrant. Transfer the vegetable mixture to the slow cooker or bowl with the meat.

Wipe the pan clean and warm 1 tablespoon of leftover bacon grease over medium heat (use vegetable oil if no more bacon grease remains). Cook the mushrooms with 1/4 teaspoon salt until they have release all their liquid, the liquid has evaporated, and the mushrooms are golden brown, 8 to 10 minutes. Transfer the mushrooms to a clean bowl and set aside — keep the mushrooms separate from the meat and onion mixture (they get added later).

Stir the beef cubes and vegetables together in the slow cooker with 1 teaspoon of salt. Tuck the sprigs of thyme and the bay leaf into the mixture. Pour the stock and the remaining wine over the beef and vegetables — the liquid should come about 3/4 of the way to the surface of the ingredients.

Cover the slow cooker and cook on low for 6 to 8 hours. When finished, the beef should fall apart easily with a fork.

Once the meat is cooked, stir in the reserved bacon and mushrooms. Cook with the slow cooker on high or simmer in the Dutch oven over medium heat until the mushrooms are warmed through, about 10 minutes.

Serve in bowls over noodles or with crusty bread on the side. Sprinkle with parsley before serving. Leftovers will keep for up to a week or can be frozen for up to three months.