01 -
Set a 6-quart Instant Pot to High Sauté. Add butter and let melt. Add mushrooms with a generous pinch of salt and pepper. Cook, stirring occasionally, until golden and liquid has evaporated, about 5-6 minutes.
02 -
Stir in the shallots and thyme. Cook until shallots are softened, about 2 minutes.
03 -
Add orzo, chicken broth, lemon zest, and lemon juice. Do not stir. Gently shake the pot if needed to evenly distribute orzo.
04 -
Place frozen chicken breasts on top of the orzo, not submerged. Season the chicken with salt and pepper.
05 -
Secure the lid. Set to Pressure Cook on High for 10 minutes.
06 -
Allow 10 minutes natural release, then carefully quick-release any remaining pressure. Open lid cautiously.
07 -
Remove chicken and slice or shred. Stir spinach, heavy cream, and Parmesan into the orzo. Let sit 2-3 minutes to wilt the spinach and thicken the sauce. Taste and adjust seasoning. Serve with sliced chicken.