Garlic / Onions / Peppers - Prep as directed. (Can be done up to 3 days ahead)
Make sauce - Mix together Italian seasonings, salt, red pepper flakes, garlic, tomato paste, diced tomatoes, wine and chicken stock. (Can be done up to 3 days ahead.)
Chicken - Remove skin from chicken. Try using scissors if you have trouble getting the skin off. (Can be done up to 1 day ahead)
Start slow cooking (~8 hours before) - Nestle chicken into bottom of slow cooker. Sprinkle with salt and pepper and tenderize with a fork. Layer in onions and peppers and then pour on the sauce. Slow cook on low for 8 to 9 hours, until chicken easily comes off the bone. Season to taste with salt and pepper. (Can be done up to 5 days before and then stored in the fridge in air-tight containers)
Quinoa - Combine quinoa with 2x the amount of water in a saucepan. Add in a generous dash of salt. Bring to a boil covered. Lower heat, keep covered, and cook until liquid is absorbed, 8 to 10 minutes. (Can be done up to 5 days ahead)
Chop parsley and slice lemons. Enjoy your warm cacciatore sprinkled with parsley over quinoa. Serve with lemon wedges to add some brightness!