Prep the ingredients. Dice the onion, celery, and peppers.
Slice the sausage and cut the chicken into bite-size pieces. Mince the garlic.
Optional browning for extra flavor. In a skillet, heat olive oil over medium-high. Brown the sausage for 2–3 minutes and sear the chicken just until lightly golden.
This step is optional but adds a nice smoky, caramelized note.
Layer the slow cooker. Add onion, celery, bell peppers, and garlic to the slow cooker. Place the chicken and sausage on top.
Mix the sauce. In a bowl, stir together crushed tomatoes, chicken broth, tomato paste, Cajun seasoning, thyme, smoked paprika, and a few dashes of hot sauce. Taste the mixture; if your Cajun seasoning contains salt, hold off on adding more salt until the end.
Combine and cook. Pour the sauce over the meat and vegetables.
Add the bay leaf. Cover and cook on Low for 6–7 hours or on High for 3–4 hours, until the chicken is tender.
Adjust seasoning. Remove the bay leaf. Taste and season with salt and pepper.
Add more hot sauce if you like it spicier.
Serve with rice. Spoon the jambalaya over warm cooked rice. Garnish with sliced green onions and parsley.
Make it thicker (optional). If you want a thicker base, remove the lid for the last 20–30 minutes on High to reduce slightly, or stir in a slurry of 1 teaspoon cornstarch mixed with 1 tablespoon water and cook 10 more minutes.