Pour the full bottle of Pinot Noir into a medium saucepan over high heat. Bring to a boil and cook for 15 minutes until reduced by half. Set aside.

Preheat the slow cooker insert or a cast iron skillet over high heat. Add the diced bacon and cook until crisp. Remove and set aside, leaving at least 2 tablespoons of bacon fat in the pan.

Season the chicken thighs with half the kosher salt and all of the black pepper. Add them skin-side down and brown for 4 to 6 minutes per side until deep golden. Remove and set aside.

Add the mushrooms and shallots to the same pan over medium-high heat. Cook for 3 minutes, stir, then cook another 3 minutes until softened.

Transfer the mushrooms and shallots to the slow cooker. Add the garlic, carrots, half the bacon, chicken broth, remaining salt, tomato paste, thyme sprigs, bay leaves, pearl onions, and reduced red wine. Stir until well combined.

Nestle the browned chicken thighs into the slow cooker, cover, and cook on low for 7 hours.

In a small bowl, mash together the butter and flour into a smooth paste. Stir it into the slow cooker. Cover and cook for 1 additional hour until the sauce thickens.

Remove the bay leaves and thyme sprigs. Top with the remaining crispy bacon, stir gently, and serve hot over mashed potatoes or egg noodles.