Preheat the oven to 375°F (190°C).
Heat olive oil in a skillet over medium heat.
Add garlic, stirring for about 30 seconds until fragrant.
Stir in the mushrooms and season with salt and pepper; cook until softened.
Add chopped spinach and cook until wilted.
Remove from heat and mix in cream cheese and Parmesan.
Prepare chicken breasts by slicing a pocket into each.
Stuff each chicken breast with the mushroom mixture.
Season the outside of the chicken breasts with salt and pepper.
Heat olive oil in an oven-safe skillet over medium-high heat.
Sear the stuffed chicken breasts for 4-5 minutes on each side.
Pour chicken broth into the skillet and transfer to the oven.
Bake for 25-30 minutes until the chicken is cooked through.
Let resting for 5-10 minutes before slicing.
Slice and serve warm with drizzled cooking liquid.