Halve, peel, and finely chop the onion. Core, seed, and remove the white veins from the bell pepper. Cut into thin strips, then cube. Cut the celery into 1/2-inch pieces. Thinly slice the scallions.

Heat 1 tablespoon olive oil in a pot over medium heat. Add the onion, celery, and half the green bell pepper. Season with salt and pepper. Cook for about 5 minutes, until softened.

Add the rice, cumin, chili powder, and pinch of cayenne pepper (careful, it's spicy!). Cook for about 1 minute, stirring, to toast.

Add the tomatoes, stock concentrate, and 2 cups of water and bring to a boil. Reduce to a simmer and cook for 15-20 minutes or until rice is tender, stirring occasionally.

Season the shrimp with salt and pepper. Add the shrimp and remaining bell pepper to the rice and stir. Cook for about 3-5 minutes, until shrimp are pink and opaque in the center.

Serve the jambalaya with a sprinkle of scallions on top!