Step 1

In a large Dutch oven, melt 5 tablespoons of the butter over medium-high. Add the onion, season with salt and pepper, and cook, stirring often, until softened and lightly browned, 3 to 6 minutes. Add the cabbage, season generously with salt and pepper, and stir to combine. Reduce heat to medium-low, cover the pot and cook, stirring occasionally, until the cabbage is tender but not mushy, 35 to 40 minutes. (Browning is welcome, but if you see burning, reduce the heat and add a tablespoon or two of water.)

Step 2

Meanwhile, bring a large pot of salted water to a boil. When the cabbage is done, remove from heat and keep covered. Add the noodles to the boiling water and cook according to package directions. Reserve 1/2 cup pasta water, then drain the noodles.

Step 3

Add the noodles, reserved pasta water and remaining 1 tablespoon butter to the cabbage. Stir over medium-high heat until the noodles are saucy and glossed with melted butter, 1 to 2 minutes. Season to taste with salt and pepper.