Preheat oven to 325 degrees F. Grease a 2-quart casserole dish with 1 tablespoon butter.
Melt 2 tablespoons butter over medium high heat in large saute pan. Add cabbage and onions and season; season with 1 teaspoon Diamond Crystal® Kosher Salt and 1 teaspoon black pepper. Stir; cover and cook for until cabbage and onions are soft, about 10 minutes.
Sprinkle in flour, stir. Cook 2 more minutes. Slowly stir in broth and cream; simmer until slightly thickened, about 2 minutes.
Bring a large pot of lightly salted water to a boil. Cook egg noodles in the boiling water, stirring occasionally until cooked through but firm to the bite, about 5 minutes. Drain.
Add cooked noodles to cabbage mixture. Stir to combine. Transfer to prepared casserole dish. Dot with 2 tablespoons butter.
Cover and bake until mixture is hot and bubbly, about 30 minutes.