First, make a roux. In a large pot heat the olive oil over medium-high heat. Sprinkle a dash of flour into the oil to see if it will bubble. When bubbling occurs, gradually whisk the remaining flour into the oil. Stir your roux constantly and thoroughly from the bottom. Keep in mind that the bottom will get darker a lot faster than the surface as it is closer to the heat. Your roux should get a lightly brown color, kind of like peanut butter. This will take about 8-10 minutes. It can just take seconds for a roux to go from "dark" to "burnt", so pay attention! If it's burnt, you have to start from the beginning again.
Then, add the onion and the vegetables and cook for another 10 minutes until the vegetables are tender and the okra slime is mostly gone.
Add the spices and cook for another minute. Then add the diced tomatoes, and the beans, and cook for 20 minutes. Season with salt and pepper.
Serve over rice and sprinkle with freshly chopped parsley.