In a medium saucepan, combine cornmeal, stock, and half the salt. Bring to a boil over medium heat, stirring constantly. Reduce to low and stir until thickened, about 20 minutes.

Once thick, add pumpkin purée, Parmesan, butter, egg, herbs, remaining salt, and pepper. Stir until combined and creamy.

In a skillet, heat oil over medium heat, add pancetta, and cook until crispy, about 3-5 minutes. Remove with a slotted spoon and drain on paper towels.

In the same skillet, sauté Swiss chard stems for 2 minutes. Add shallots and garlic, cooking for another 2-3 minutes. Add chard leaves until wilted, about 2 minutes, then add lemon juice.

If needed, reheat polenta gently, adding broth or milk for consistency. Serve polenta topped with sautéed chard and pancetta, garnished as desired.