Prep the ingredients: Bring a large pot of water with a large pinch of salt to a boil. Halve, peel, and thinly slice the onions. Remove and thinly slice the Swiss chard stems; thinly slice the leaves. Mince or grate the garlic.

Blanch the Swiss chard: Add the Swiss chard stems to the boiling water and cook for 2 minutes, until tender. Add the Swiss chard leaves and cook for another 1 minute, until wilted. Remove with a slotted spoon and set aside. Leave the water boiling on the stove—we’ll be using it later!

Cook the onions: Heat 1 Tablespoon olive oil in a large pan over medium heat. Add the onion and cook, tossing, for 5-6 minutes, until softened. Season with salt and pepper.

Cook the penne: While the onions cook, add the penne to the boiling water and cook for 9-10 minutes, until al dente. Reserve 1/2 cup pasta water then drain.

Cook the mushrooms: Add the mushrooms and another 1 Tablespoon olive oil to the pan with the onions and cook, tossing, for about 5 minutes, until golden brown. Season with salt and pepper. Add the garlic, paprika, and as many chili flakes as you like (start with a little and go up from there!).

Make the sauce: Add the sour cream and 1/2 cup pasta water to the pan. Stir to combine and cook for 2-3 minutes, until slightly thickened.

Finish and plate: Add the drained penne, Swiss chard, and half the Parmesan to the pan and toss to combine. Season with salt and pepper. Serve the penne with the remaining Parmesan and enjoy!