Step 1

Finely chop 4 slices bacon. Finely chop 1 small yellow onion (about 1 cup) and mince 2 large garlic cloves. Remove and discard casings from 1 pound spicy Italian sausage if needed.

Step 2

Place the bacon in a large pot over medium heat and cook, stirring occasionally, until golden and crisp, 6 to 8 minutes. Transfer with a slotted spoon to a paper towel-lined plate. Pour off and discard the bacon fat in the pot.

Step 3

Return the pot to medium heat. Add 1 tablespoon olive oil, the onion, and 1/4 teaspoon red pepper flakes, and cook until softened, 3 to 5 minutes. Add the garlic and cook, stirring often, until fragrant and light golden, about 1 minute. Add the sausage and cook, breaking up the meat with a wooden spoon, until no longer pink and cooked through, 5 to 7 minutes. Meanwhile, slice 1 1/2 pounds russet potatoes crosswise into 1/8 inch-thick rounds.

Step 4

Add 1 (32-ounce) carton low-sodium chicken broth, 3 cups water, and the potatoes to the pot. Bring to a boil over medium-high heat. Reduce heat to medium and simmer, stirring occasionally, until potatoes are just tender, about 6 minutes. Meanwhile, strip the leaves from the stems of 1 bunch curly kale. Discard the stems and tear the leaves into 1 to 1 1/2-inch pieces (about 6 packed cups).

Step 5

Add the kale to the soup and cook until just wilted, about 2 minutes. Add1/2 cup heavy cream, 1 tablespoon white wine vinegar, 1/2 teaspoon kosher salt, and a few grinds of black pepper, and stir to combine. Taste and season with more kosher salt and black pepper as needed. Serve topped with the bacon.