In a large pot heat the oil on medium-high heat. Stir in the flour and cook for 15- 20 minutes until it turns to a dark chocolate-like color. Make sure to stir constantly with a wooden spoon.
Heat a separate skillet on medium-high heat and add the sliced sausages and chicken. Brown them for 2-3 minutes from each side then remove to a plate.
Add the chicken broth to the skillet with the roux and bring to a boil. Add the vegetables, garlic and cajun seasoning. Boil for 10 minutes or until the vegetables are tender. Add the cooked sausage and chicken.
Serve the gumbo warm over cooked rice and garnish with parsley leaves. Enjoy!