In a large skillet, heat the olive oil over medium heat.
Add the diced onion and sauté until translucent, about 3-4 minutes.
Stir in the minced garlic and crushed red pepper flakes, cooking for another minute until fragrant.
Add the sausage to the skillet, breaking it up with a spatula, and cook until browned through, about 6-8 minutes.
Once the sausage is browned, add the chopped kale and cook until wilted, about 3-4 minutes.
Stir in the rinsed quinoa, followed by the broth. Bring to a boil.
Reduce heat to low, cover the skillet, and let simmer for about 15 minutes, or until quinoa is cooked and has absorbed the liquid.
Remove from heat and let it sit covered for an additional 5 minutes before fluffing with a fork.
Season with salt and pepper to taste before serving hot.