First Step: Preheat and Prep Begin by preheating your oven to 200°C / 390°F (fan 180°C), which sets the stage for even cooking in your mushroom stuffed chicken breast. Next, take the 2 skinless boneless chicken breasts and cut deep pockets into the folded side without cutting through this creates space for that tasty filling. Season the inside and outside of each chicken breast with half the ¾ tsp salt and ¼ tsp pepper to build flavor from the start.

Second Step: Cook the Filling Melt the 30g / 2 tbsp unsalted butter in an oven-proof skillet over high heat, then add the 200g / 7oz sliced mushrooms and cook for 3 minutes until they turn golden this step locks in their earthy essence for the savory herb filling. Stir in the 2 finely minced garlic cloves, the remaining salt and pepper, and ½ tsp thyme leaves, cooking for another 2 minutes to deepen the flavors. Add the 2 cups of baby spinach and stir for 30 seconds until it wilts, creating a vibrant mix that’s ready to stuff.

Third Step: Stuff and Seal Stuff the mushroom-spinach mixture into the pockets of your chicken breasts, then top it with 80g / 3oz sliced mozzarella for that melty finish in your mushroom stuffed chicken breast. Seal everything with 2 3 toothpicks placed diagonally to hold the filling securely, but don’t worry, they just need to keep things in place loosely. For dietary tweaks, if you’re going low-calorie, use less cheese here to cut back without losing the fun.

Fourth Step: Sear the Chicken Wipe your skillet clean, heat 1 tbsp olive oil over medium-high heat, and sear the stuffed chicken breasts for 1.5 minutes per side until they get a nice golden color this step adds a crispy edge and enhances the overall taste of your mushroom stuffed chicken breast. It’s a simple way to lock in juices, and if you’re adapting for someone with preferences, you could swap olive oil for a different fat source. Keep an eye on the time to avoid overcooking at this stage.

Fifth Step: Bake and Rest Transfer the skillet to the preheated oven and bake your mushroom stuffed chicken breast for 15 minutes, checking that the internal temperature reaches at least 65°C / 149°F for safety note that some recommend 75°C / 165°F. Once done, rest the chicken on a plate loosely covered with foil for 5 minutes; this lets the flavors settle and keeps everything moist. For variations, if you’re making this for dietary needs, adjust herbs like using oregano instead of thyme for a fresh twist.