Bring a large pot of salted water to a boil for the noodles.
In a large Dutch oven, melt 1 T of the butter over medium heat and add the pancetta. Cook, stirring, until crisp, 12 to 14 minutes.Remove the pancetta to a paper-towel-lined plate to drain. Reserve.
Strain the fat from the pancetta from the pot, wipe the pot clean, add back in 2 T of the pancetta fat, and melt the remaining butter along with it in the pot. Reserve the remaining pancetta fat for another use or discard.
Add the onions, cabbage, carrots, and thyme.Season with the salt and half of the pepper. Stir to coat the vegetables with the butter. Cover and cook until the cabbage is wilted and almost tender, about 10 minutes. Uncover and simmer until the cabbage is very tender, about 10 minutes more.
While the cabbage cooks, add the noodles to the boiling water and cook according to the package directions.
Increase the heat under the Dutch oven to high and cook, stirring, until the cabbage and onions are golden, about 10 to 12 minutes. Add in the minced garlic and capers. Cook for 1 minute and add the peas, then deglaze the pan with the white wine and add the lemon juice. Add three quarters of the pancetta, combine well, and remove from the heat.
Drain the noodles and add to the pot with the cabbage. Toss well to coat the noodles with the cabbage and onion mixture. Sprinkle with the parsley and the remaining reserved pancetta.Serve immediately.