Sautéed Swiss Chard with Parmesan

INGREDIENTS

• 2 tablespoons butter
• 2 tablespoons olive oil
• 1 tablespoon minced garlic
• 1/2 small red onion, diced
• 1 bunch Swiss chard, stems and center ribs cut out and chopped together, leaves coarsely chopped separately
• 1/2 cup dry white wine
• 1 tablespoon fresh lemon juice, or to taste
• 2 tablespoons freshly grated Parmesan cheese
• salt to taste (optional)