Using sauté setting – add oil to cooker, along with mushrooms, salt, and pepper. Cook for about 10 minutes, stirring occasionally. After about 5 minutes, add garlic, thyme, and vinegar – mix well. Continue cooking until most (not all) of the liquid has evaporated. Remove from cooker and set aside.
Give pot a quick wipe or rinse, then add sausage and onions. Cook until sausage has browned and onions are soft and translucent. Return mushrooms to cooker and give a good stir.
Add chicken broth and pumpkin - mix well to combine everything. Then add kale and give a good mix, trying to submerge all the greens.
Lock lid and cook at high pressure for 10 minutes. Once cook time is complete, quick-release pressure.
Remove lid, add milk, and mix well. Serve and enjoy!