Place a large non-stick skillet over medium heat then add 3Tbsp of butter and melt completely. Add onion, bell pepper, celery and garlic. Cook for 3–4 minutes—until onion and bell pepper have begun to soften.
Add uncooked quinoa then stir to combine. Cook for 1 minute, toasting the quinoa, then pour in chicken broth. Bring mixture to boil, reduce heat to low then add oregano and thyme. Stir to combine then cover and let simmer for 15 minutes.
After quinoa has simmered for 15 minutes, remove lid then stir. Add shrimp then arrange on top of the quinoa. The shrimp will probably cover the entire top of the dish, so you may have to nestle a few of them into the mixture. Replace lid then allow shrimp to simmer for 3–4 minutes, or until cooked through.
Remove lid and test quinoa for doneness. You’ll know quinoa is done when it’s completely soft but still ‘pops’ a bit when eaten. The quinoa should have absorbed nearly all of the liquid at this point, but it will continue to absorb moisture as it sits.
Remove skillet from heat. Melt remaining 3 Tbsp of butter in microwave. Stir garlic salt and red pepper flakes into melted butter then drizzle over shrimp. Sprinkle the top with fresh parsley and serve immediately with lemon wedges on the side. Enjoy!
If you don't want to use butter, you can substitute with the same amount olive oil.