butter, plus more for baking dishes • Coarse salt and ground pepper • penne rigate • olive oil • boneless, skinless chicken breast halves (8 ounces each), halved horizontally • plus 2 tablespoons all-purpose flour (spooned and leveled) • garlic cloves, minced • whole milk • white mushrooms, trimmed and thinly sliced • oil-packed sun-dried tomatoes, drained and thinly sliced • shredded provolone (6 ounces) • finely grated Parmesan (4 ounces)