Preheat your oven to 400°F (200°C).
Clean and slice the cremini mushrooms, then toss them on a baking sheet with 0.5 tbsp of melted ghee, sea salt, and black pepper.
Roast the mushrooms for 15 minutes until they are golden brown and tender.
While the mushrooms roast, slice the chicken breast into strips and season lightly.
Heat the remaining 0.5 tbsp of ghee in a large skillet over medium-high heat and sear the chicken until cooked through and slightly browned.
In a small bowl, whisk together the Greek yogurt, minced garlic, lemon juice, and fresh thyme to create the creamy base.
Add the baby spinach to the skillet with the chicken and stir for 1 minute until just wilted.
Remove the skillet from the heat and stir in the roasted mushrooms and the yogurt mixture until everything is coated in a silky, creamy sauce.