1 tablespoon olive oil
3 garlic cloves, smashed
1 (14 oz.) Spanish onion
1 green bell pepper, sliced into 1/2-inch wide strips
1 yellow bell pepper, sliced into 1/2-inch wide strips
1 (8 oz.) package baby bella mushrooms, quartered
1 (4 lb.) broiler chicken, quartered
1 teaspoon kosher salt
Freshly ground black pepper
1 (28 oz.) can crushed tomatoes
1/2 pound uncooked rotini
1/4 cup finely chopped fresh parsley
Freshly grated Parmesan cheese, for serving
Heat oil in a small skillet over medium heat. Add garlic and cook, stirring, until golden, about 2 minutes; transfer to slow cooker.
Add onion, bell pepper and mushroom. Put chicken on top; sprinkle with salt and pepper. Pour in crushed tomatoes; cover and cook for 4 hours on high or 8 hours on low. Chicken should be very tender.
Bring a pot of salted water to a boil and cook rotini according to package directions until al dente. Drain and transfer to a large serving bowl.
Transfer chicken to 4 plates. Skim fat from surface of sauce and discard. Stir parsley into sauce. Spoon some sauce over chicken. Serve remaining sauce with pasta and cheese.