Cook the sweet potatoes. Wash and poke several holes in the sweet potatoes, then cook them in the microwave using the potato preset. Let them cook while you prepare the rest of the recipe. Once done, remove from the microwave, cut in half, and let them cool until they're safe to handle.
Prep the kale. Remove the leaves from the ribs, tear into pieces, wash, and set aside.
Sauté the onion. Heat the olive oil in a large skillet over medium heat and cook the onion for 2-3 minutes, until softened.
Cook the turkey. Add the ground turkey and cook until browned and fully cooked through.
Add seasonings. Stir in the minced garlic, kosher salt, pepper, and thyme, and cook for another minute.
Wilt the kale. Reduce the heat to low and stir in the kale until wilted.
Prepare the sweet potatoes. While the kale is cooking down, carefully peel and chop the cooled sweet potatoes into large cubes. Make sure the sweet potatoes are cool enough to handle before attempting this step.
Combine everything. Gently stir the sweet potato pieces into the turkey and kale mixture.
Add the cheese. Top the dish with the shredded Gruyère and let it melt, either by covering the pan or placing it under the broiler for a few minutes.
Serve. Divide the dish into four equal portions and dig in!