01 - Bring chicken broth and milk to a gentle boil in a heavy saucepan over medium heat. Slowly whisk in cornmeal. Reduce heat to low, stirring consistently until thick and creamy, approximately 15 minutes.
02 - Remove pan from heat. Stir in Parmesan cheese, butter, salt, and black pepper until smooth and well combined.
03 - Pour polenta mixture into a parchment-lined 8x8-inch baking dish. Spread evenly and cool to room temperature. Transfer to refrigerator and chill for at least 1 hour until firm.
04 - Heat olive oil in a large skillet over medium-high flame. Add pancetta, cooking for 5 minutes until crisp. Stir in Brussels sprouts, season with red pepper flakes, and sauté until tender with golden edges, around 7 minutes.
05 - Once solidified, lift polenta from pan using parchment edges and cut into 16 squares. Heat a nonstick skillet over medium, add squares, and toast each side for 2-3 minutes until golden.
06 - Top each toasted polenta square with Brussels sprouts and pancetta mixture. Garnish with freshly chopped chives and serve warm.