1/2 cup plus 2 tablespoons grated Parmesan cheese, divided
Place broccoli and cauliflower in a steamer basket; place in a saucepan over 1 in. of water. Bring to a boil; cover and steam for 5-8 minutes or until crisp-tender.
Meanwhile, in a small bowl, combine the broth, cream and mustard. In a small saucepan, melt butter. Stir in the flour, onion powder and pepper until smooth. Gradually stir in broth mixture. Bring to a boil; cook and stir for 2 minutes or until thickened. Remove from the heat. Stir in 1/2 cup Parmesan cheese.
Place vegetables in a serving bowl; drizzle with sauce and sprinkle with remaining Parmesan.