Preheat the oven to 350 degrees F. Line a 9" x 13" baking pan with parchment paper. Set the polenta in the pan, slightly overlapping the rounds if needed. Drizzle with 1 Tbsp. olive oil; sprinkle with the Parmesan cheese. Bake for 20 minutes, until hot and light golden.
Meanwhile, heat the remaining 2 Tbsp. oil in a very large, wide skillet set over medium to medium-high heat. Add the mushrooms and cook until tender and the moisture has been simmered out of them, about 5 to 7 minutes. Add the tarragon and wine and simmer until the wine is reduced to about 2 Tbsp.
Add the cream, bring to a simmer, and simmer and reduced a bit until lightly thickened. Divide the polenta among 4 heated shallow bowls. Divide and top with the mushroom mixture. Divide and top with cheese, chopped parsley and serve.
Note: Tubes of ready to use polenta are available in our deli department.