In a large Dutch oven or heavy lidded pot, heat 2 tablespoons oil over medium-high. Add the mushrooms, season generously with salt and pepper, and cook, stirring occasionally, until browned, 8 to 10 minutes. Add the garlic and oregano and cook, stirring, until fragrant, about 2 minutes. Transfer to a bowl.

Add the remaining ¼ cup oil to the pot. Add the onion, carrot and celery, season generously with salt and pepper, and cook, stirring occasionally, until softened and caramelized, about 10 minutes. Add the tomato paste and cook until fragrant, 1 to 2 minutes.

Return the mushroom mixture to the pot and stir in the red wine. Cook, stirring occasionally, until the pan is almost dry, about 5 minutes. Add the tomato passata or purée and 1 cup of water used to swish out the bottle or can.

Bring the sauce to a bubble and then reduce to a simmer over medium-low and cook for 30 minutes, uncovered, stirring occasionally.

Make the pangrattato (if using): While the pasta sauce simmers, heat oil in a medium pan over medium. Add chopped walnuts, toss to coat and cook, stirring frequently, until fragrant and toasted, 2 to 3 minutes. Stir in the bread crumbs and salt and cook for 2 more minutes, until toasted. Remove from the heat and mix in the parsley. Set aside to cool.

the pasta in salted water according to package instructions until al dente. Drain, reserving 1 cup pasta water.

Toss the pasta in the sauce, adding pasta water as desired to thin the sauce and allow it to adhere to the pasta. Season to taste with salt and pepper.

Divide the dressed pasta among bowls. Top with the pangrattato, if using, and perhaps Parmesan, if desired.