8 sprigs tarragon, reserving some leaves for garnish
125 grams prosciutto, cut or ripped into short strips
For the baskets:
Cover a baking sheet with parchment paper. Sprinkle grated cheese into four rounds about 15 centimeters wide. Cook in oven for seven to eight minutes, until golden. Remove from oven and carefully place on an upside-down ramekin. Leave to form into basket shape.
For the polenta:
Heat milk in a large saucepan over high heat, then add polenta slowly, whisking as you do. Bring to a boil, then lower heat to medium-low and continue to cook, stirring often with a spatula or wooden spoon, making sure to scrape the sides and bottom of the saucepan. Cook until polenta is slightly thick, about 15 minutes, then remove from heat and stir in butter and lemon zest. Season with salt.
For the toppings:
Heat the butter and olive oil in a pan over medium-high, then add mushrooms and cook for five to seven minutes, stirring frequently, until mushrooms are golden. Add garlic and tarragon sprigs and cook for another one to two minutes.
When the baskets have cooled completely, and the polenta is ready, place each basket on a serving dish and fill ¾ full with the polenta, then top with the mushroom mixture and torn prosciutto. Garnish with grated Montasio cheese and torn tarragon leaves. Serve immediately.