Season the chicken thigh pieces with ½ teaspoon salt and ½ teaspoon pepper. Let rest while you prep the vegetables. This allows the seasoning to seep into the meat.
Heat a large saucepan over medium-high heat, spray with oil and brown the chicken pieces on all sides. Do this in two batches so the chicken pieces fit into the saucepan in a single layer. Transfer the chicken to a bowl and set aside.
Spray the saucepan again and add the olive oil. Add the onion and cook until tender and starting to brown, about 5 minutes. If the onion is drying out while cooking, add 2 tablespoons hot water, scraping the browned bits from the bottom of the saucepan (use a wooden spoon).
Add the carrots, celery, garlic, bacon, ¼ teaspoon salt and ¼ teaspoon pepper. Cook until the fat renders out of the bacon and the bacon starts to brown on the edges, 5 to 6 minutes. Add the tomato paste and cook, stirring constantly, for 2 minutes.
Stir in the potatoes, beer, 1 ½ cups chicken broth, thyme and bay leaves. Bring to a boil, then reduce heat so the mixture maintains a lively simmer. Cover the saucepan and cook until the potatoes are tender, about 50 minutes. About 15 minutes into cooking, add the chicken and any accumulated juices.
If the potatoes aren't tender yet and there doesn't appear to be enough liquid, add more chicken broth (¼ to ½ cup).
Place the flour in a medium bowl. Gradually whisk in ½ cup of the stew cooking liquid (careful, it will be hot!) and ¼ cup chicken broth to form a slurry. Whisk until smooth. Add the mixture to the stew.
Simmer the stew, uncovered, until thickened, about 10 minutes. Taste and adjust seasonings as needed. Stir in the parsley. Serve.
Notes
Be sure the potato pieces aren't bigger than ¾-inch, otherwise they'll take too long to cook.Please note that I am not a medical or nutritional professional. I provide nutritional information for my recipes as a courtesy to my readers. It is calculated using the built-in recipe card calculator. While I attempt to provide information that is as accurate as possible, you should calculate the nutritional information independently before relying on it.