Add the shrimp, cajun seasoning, red pepper flakes, chopped garlic, and olive oil to a bowl. Marinate in the fridge for at least 15 minutes or up to 2 hours.
Heat the butter over medium heat in a large skillet. When the butter is melted and starting to sizzle, add the shrimp (ideally in one layer) and cook 2-3 minutes on both sides. The shrimp is done cooking when it's no longer translucent. Using a slotted spoon remove the shrimp and set it aside. Don't wipe the skillet clean.
To the same skillet melt the remaining butter and toast the orzo for about 3 minutes until lightly golden.
To the orzo add the rice, onion powder, garlic powder, salt, pepper. Mix to combine.
Add the broth, bring to a simmer and cook for about 20 minutes until the rice is cooked through. If the broth evaporates too quickly lower the heat a bit and add more broth (or water) ¼ cup at a time.
To the finished rice, stir in the fresh chopped parsley.