Dice the sweet potato small this step matters more than it seems: Cut the peeled sweet potato into even ½-inch cubes. Keeping the pieces this small is what lets the sweet potato finish cooking in the same 8–9 minutes it takes the tortellini to cook through larger chunks either stay firm in the center or force you to simmer the pasta well past al dente waiting for them to soften.

Sauté the aromatics: Heat the olive oil in a large deep skillet over medium heat. Add the onion and cook for 3 minutes, until softened, then stir in the garlic and cook for 30 seconds more, until fragrant.

Add the sweet potato and broth: Stir in the diced sweet potato and broth, and bring to a gentle simmer. Cover and cook for 6–7 minutes, until the sweet potato is just starting to soften at the edges.

Add the tortellini and cream: Stir in the tortellini and heavy cream, then return to a gentle simmer, uncovered. Pro tip: stir occasionally but not constantly here too much stirring at this stage can break up the tortellini before it’s fully cooked.

Cook until the sauce thickens: Continue simmering for 8–9 minutes, until the tortellini is tender and the sauce has reduced and thickened enough to coat the back of a spoon. It’ll look thin at first, but it comes together noticeably in the last two or three minutes.

Wilt the spinach and finish: Stir in the chopped spinach, parmesan, and nutmeg, and cook for 1–2 minutes more, until the spinach wilts down and the parmesan melts into the sauce. Season with salt, pepper, and red pepper flakes if using.

Serve right away: This skillet is best served immediately while the sauce is at its silkiest.