Garlic Shrimp and Swiss Chard on Polenta

Combine water, milk, and salt in a medium saucepan and slowly bring to a boil over medium-low heat. Meanwhile, heat 2 Tbsp of the oil in a large, deep nonstick skillet over medium-high heat; add shrimp and red onion. Sauté 2 minutes; add garlic and continue to sauté 1 minute, just until shrimp turn opaque and onion is almost translucent. Remove mixture to a plate. Add remaining 1 Tbsp oil to skillet and sauté chard stems over medium heat 2 minutes. Top with wet chard leaves; cover skillet with lid and cook 1 minute until leaves are wilted. Uncover; continue to sauté 2 minutes. Add tomatoes with their juice and simmer 4 minutes. Bring water-milk mixture to a full boil; slowly whisk in polenta until smooth. Cook over medium-low heat 3 minutes, stirring until thick and creamy. Remove from heat; stir in butter and cheese. Raise heat on chard mixture and add shrimp mixture. Cook 2 to 3 minutes longer, until shrimp are cooked through. Serve shrimp mixture on polenta; season with pepper to taste.