In large shallow straight-sided pan, such as cast iron 3.5 or 4-quart braiser, over medium heat melt butter and sauté shallots just until tender. Add mushrooms. Sauté just until tender. Add milk, vegetable stock, seasonings, orzo, and swiss chard ensuring pasta is completely covered by liquid. Bring to a low boil; and cook until the pasta is al dente and liquid has nearly evaporated, about 15 minutes, stirring frequently. Remove from heat and stir in 1 cup of parmesan cheese until well combined. Serve from cooking pan or divide evenly among serving bowls and garnish with remaining cheese.