Wash all of your greens and roughly chop, then set aside.
Make a dark chocolate roux: This requires constant attention and stirring so you will not be able to leave the pot for several minutes. Start by warming the olive oil in a large stock pot over medium high heat until the oil shimmers. Whisk in the flour with a wire whisk until clumps are broken up. Using a wooden spoon, stir and cook the oil/flour mixture for about 15 minutes until it turns a dark brown color, like a chocolate bar. It should begin to smell like nutty popcorn. Stir constantly so that none of the flour burns.
When you have a dark brown roux, stir in the scallions. Cook until lightly wilted, about 2 minutes.
Stir in the stock
Work all the greens into the stew a bit at a time until they are wilting.
Bring to a boil and skim any foam that rises to the surface.
Add the bay leaf, garlic powder, thyme, and salt and pepper to taste.
Stir in the Cajun seasoning a 1/2 tbsp at a time and taste as you go to reach desired spiciness.
Cover then reduce heat to low and simmer about 30 minutes, stirring occasionally.
Season to taste with salt and pepper and serve over cooked rice if desired.