Brussels Sprouts Pizza with Balsamic Red Onions

Ingredients (11)

• 1 to 2 tablespoons olive oil
• 2 medium or 1 extra-large red onion
• Pinch red pepper flakes
• Dash salt
• 1/4 cup balsamic vinegar
• 8 ounces (1/2 pound) Brussels sprouts
• 1 1/2 to 2 teaspoons olive oil
• Salt and freshly ground black pepper
• 1 batch easy whole wheat pizza dough or store-bought whole wheat dough (I used Trader Joe's)
• 1 1/2 to 2 cups grated low-moisture part-skim mozzarella cheese (6 to 8 ounces), depending on how cheesy you like your pizza
• 1/4 cup grated Parmesan cheese