Heat olive oil in a saucepan over medium heat. Transfer sausage links into the hot pot. Cover with a lid and cook until beautifully browned and just barely cooked through, about 5 minutes per side.

While the sausages are cooling, add wine to the same pot over medium-high heat. Simmer until it reduces by about half, 1 to 2 minutes.

Add marinara sauce. Pour water into the jar of pasta sauce, seal, and shake to rinse out the jar. Pour that liquid into the pot and return to a simmer. Reduce heat to low.

Slice each fully cooled sausage into 4 pieces. Transfer sausage and any accumulated juices into the simmering sauce. Cook at a gentle, steady simmer for 1 hour.

Meanwhile, bring a large pot of generously salted water to a boil. Cook spaghetti in the boiling water until nearly tender, about 10 to 11 minutes. Drain and mix with the hot sauce.

Evenly divide pasta onto 4 plates and top each serving with sausage pieces. Sprinkle with Parmigiano-Reggiano and parsley.