Heat 2 tablespoons olive oil in the bottom of a heavy soup pot over medium high heat, or using the sauté function of an electric pressure cooker. Sauté the Italian sausage and onion together for about 5 minutes, breaking up the sausage into small pieces.
Add 1 clove pressed garlic, ½ teaspoon kosher salt, Italian seasoning, red pepper flakes and carrots, and continue to sauté another 5 minutes.
Add the potatoes, kale, tomatoes, chicken broth and bay leaves, and stir to blend.
Place the lid on the pressure cooker and set the valve to “seal.” Press the “soup” button, then press the “adjust” button to select the “less” setting, This will cook the soup at medium high pressure for 20 minutes. Alternatively, you can cook the soup at high pressure for 15 minutes using the “manual” setting.
If cooking on the stovetop, bring the soup to a low boil and cook for 30-40 minutes.
Meanwhile, cook the pasta in a separate pot, following the package instructions for al dente. Drain and rinse the beans.
Prepare the pistou by blending the basil leaves, 2 cloves pressed garlic, 2-3 tablespoons olive oil, grated Parmesan, vinegar, kosher salt and black pepper, using a food processor or mortar and pestle.
After the pressure cooking cycle is completed, wait 10 minutes for natural pressure release. Carefully move the valve to "venting" to release remaining pressure.
Remove the lid from the pressure cooker and remove the bay leaves. Stir in the cooked pasta and beans.
If cooking on the stovetop, stir in the pasta and beans at the end of the cooking time.
Ladle the soup into serving bowls, and top each serving with a spoonful of pistou.