Preheat the oven to 375°F (190°C). Lightly butter the bottom of a suitable baking dish (about 13 x 9 x 4 inches).

Season both sides of the chicken breasts generously with salt, lemon pepper seasoning, and paprika. Place the breasts flat-side down in the prepared dish.

Bake the chicken uncovered for 15–20 minutes, until it begins to set but is not completely cooked through.

While the chicken bakes, heat 1 tablespoon vegetable oil in a large skillet over medium heat. Add the fresh spinach, cover, and cook 1–2 minutes until it wilts and is heated through.

Remove the pan from the heat, stir in the minced garlic and the half-and-half, then return to medium-high to bring the mixture to a gentle boil.

Add the shredded mozzarella and stir continuously until it melts and the sauce becomes smooth, about 30–60 seconds. Lower the heat and simmer briefly to thicken, season with salt to taste, then remove from heat.

In a separate skillet, heat 1 tablespoon vegetable oil over medium-high heat. Add the sliced mushrooms and cook 1–2 minutes without salting so they can caramelize evenly.

Remove the partially baked chicken from the oven. Spoon a generous amount of creamed spinach over each breast, then top with chopped bacon, the caramelized mushrooms, and broken slices of Pepper Jack cheese.

Return the dish to the oven and bake uncovered for an additional 15–20 minutes, until the chicken is cooked through and no longer pink in the center. If you want browned cheese, broil for 2–4 minutes at the end—watch closely to prevent burning.