Bring a large pot of salted water to a boil for the noodles.
In a large Dutch oven, melt 1 tablespoon 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 into a bowl and wipe the pot clean.
Add back in 2 tablespoons of the pancetta fat and melt the remaining 3 tablespoons butter in the pot. Reserve the remaining pancetta fat for another use or discard.
Add the onions, cabbage, carrots and thyme. Season with 1 teaspoon salt and half 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 more minutes.
While the cabbage cooks, add the noodles to the boiling water and cook according to the package directions.
Increase the heat to high and cook, stirring, until the cabbage and onions are golden, 10 to 12 minutes.
Add in the garlic and capers and cook for 1 minute.
Add the peas, deglaze the pan with the white wine and add the lemon juice.
Add in three-quarters of the pancetta, combine well and remove from 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, remaining pancetta and remaining pepper.
