Bring a pot of lightly salted water to a rolling boil over high heat. Stir in the egg noodles and return to a boil. Cook, uncovered and stirring occasionally, until the noodles are cooked through but still firm to the bite, about 5 minutes. Drain.
Meanwhile, heat a large frypan over medium-high heat and stir in the pork mince, sage, green capsicum and onion. Cook and stir until the pork is crumbly, evenly browned and no longer pink, about 10 minutes. Drain and discard any excess grease.
Bring the 4 cups of water to a boil in a large pot. Stir in the cabbage, the pork mixture and the noodles. Simmer over medium-low heat, stirring occasionally, until the cabbage is tender, about 30 minutes. Add water while cooking if needed; the mixture should not be dry. Season to taste with salt and pepper. Garnish with sour cream if desired.