Using sauté setting – add 1 tablespoon olive oil and mushrooms. DO NOT add any salt at this point (something you’ll rarely hear me say, since you should season as you go). We want to brown the mushrooms and if we add salt now they will sweat. Add thyme leaves and cook them for a few minutes before touching them, allowing them begin to caramelize slightly. Once they have browned slightly on all sides, hit them with a 1/4 teaspoon of salt and remove right away. Set aside.
Add 1 tablespoon olive oil to pot, along with onions and 1/4 teaspoon of salt. Cook for about 4-5 minutes, stirring frequently, until onions are soft and translucent.
Add fennel seeds and sage. Mix well and allow to toast for a a minute or two, stirring frequently. You want them to become fragrant and begin to release their oils (they've been sitting in a jar for who knows how long).
Add turkey to pot, season with salt and pepper, and break up as much as possible. Then leave it be for a few minutes to begin the browning process. Stir occasionally. Once turkey is fully broken up and nearly fully cooked, add garlic, mix well, and cook for another minute or two.
Return mushrooms to pot, along with chicken broth and sweet potatoes. Lock lid and cook for 4 minutes at high pressure. Once cook time is complete, quick-release pressure.
Using a potato masher, gently mash sweet potatoes to break them up. Add milk and mix well. Finally, add spinach and continue mixing until wilted. Serve immediately and enjoy!