Make a roux with oil and flour until it turns a light brown. Stir in vegetables and parsley. Cook until vegetables are limp.
In large saucepan, heat broth to a boil. Slowly add roux and vegetable mixture (about 1/2 cup at a time). Wisking after each addition until the mixture becomes smooth. Add seasonings and simmer for 30 mins.
Add shrimp, cook until shrimp turns pink and is done. Garnish with green onions. Serve with rice.