Heat up your oven to 375 F. In order to make Chicken Chasseur with a crispy skin, heat up clarified butter (or a combination of butter with cooking oil) in a cast iron skillet on medium heat. Season the chicken with salt and pepper and once your pan is hot, add chicken (skin side down) and cook undisturbed for 6-7 minutes, until the skin is nicely browned.
Turned the chicken over and cook for another 4-5 minutes. Transfer the chicken onto a baking sheet and place in the oven for about 15-20 minutes, until the chicken is cooked through and the internal temperature shows 165F.
Once you've moved your chicken to the oven, discard all but 2 tablespoons of fat from the skillet. Add sliced mushrooms, season with salt and pepper, and cook for about 5 minutes. Then add chopped shallots and let them sweat for another few minutes.
If using, add cognac and either flambe it or let it almost entirely cook-off. Add wine and deglaze the pan. Cook until about 1 tablespoon of liquid is left.
Add tomatoes or tomato paste, chicken stock, and let cook for about 10-15 minutes.
If your sauce is too liquidy, combine 1-2 tablespoons of either Wondra flour or all-purpose flour with a 1/2 cup of water, mix well (until smooth) and add to the sauce to thicken it up. Cook for another 2 minutes.
Adjust seasoning, add salt and pepper as needed. Once the sauce has the right consistency, turn it off and add 2 tablespoons of cold butter and let it melt into the sauce (Tip: once you've added butter, then you cannot reduce the sauce more as the butter would break);
Chop tarragon and parsley. Remove the chicken from the oven. Then for serving, you can either put the chicken back into the pan and sprinkle everything with herbs and serve it family style, or you plate the chicken and drench in your sauce, then sprinkle with herbs. Serve with mashed potatoes or egg noodles. Enjoy!