Using a casserole pot, cook the bacon over medium heat until browned but not too crispy then with a slotted spoon transfer to a small bowl. Season the chicken with salt and pepper, increase the heat to medium-high. Working in batches, cook the chicken until golden brown, about 5 minutes per side. Transfer the chicken to a plate.
Add the onions and mushrooms to the pot and cook, stirring occasionally, until they begin to soften, about 2 minutes; season.
Stir in the tomato paste, thyme and garlic. Add the wine and cook, scraping up any browned bits, until the wine is reduced by half, about 5 minutes.
Add the stock and bring to a simmer. Return the chicken and any juices to the pot. Reduce the heat to low, partially cover and gently simmer, turning the chicken once or twice, until the chicken is cooked through and the onions are tender, about 40 minutes.
In a small bowl, dissolve the corn-starch in 3 tbsp. water. Transfer the chicken to a plate. Increase the heat to medium-high and bring the cooking liquid to a boil. Add the corn-starch mixture and stir until thickened, about 3 minutes; season.
Return the chicken and bacon to the pot, stirring tocoat. Serve in shallow bowls with crusty bread.