Using a pairing knife, butterfly chicken by cutting horizontally halfway, creating a small cavity. Take care not to cut the chicken all the way through. If the butterflied chicken breast it too thick around the top edge, pound it gently to thin out a bit.
Mix all the ingredients for stuffing.
Stuff inside the chicken pockets, about 2-3 heaping tablespoons to each breast. There is nothing called overstuffing, so don't worry.
Pull together the edges and Seal with toothpicks like you are stitching them together. If you are finding it difficult to use toothpicks, use kitchen twigs and tie the breast bringing together the open edges.( the easier way).
Mix together the garlic powder, paprika, salt, and pepper for seasoning. Coat stuffed chicken breast generously with the seasoning on both sides.
Heat oil in a cast iron skillet to medium-high heat. Place stuffed chicken top side down and sear for 2-3 minutes until its golden brown in colour. Carefully flip and sear for another 2 minutes. ( ref note 3).
Transfer the skillet to the oven and bake seared chicken breast in the oven for 12-15 minutes depending on the thickness.
Rest it for 5 minutes before serving.
Notes
You can use a mix of mozzarella and sharp cheddar,also add some parmesan cheese to the stuffing.
Cream cheese and cheddar already have salt in them, so add extra salt accordingly.
Though the recipe is for 3 chicken breasts, the photos in the post shows only 2 because it was not large enough to cook all the three together.