Beer mac and cheese - Le Coup de Grâce

Ingredients

• About 450g/500g of small shells pasta ( or macaronis )
• 1 tablespoon butter
• 2 garlic cloves, finely chopped
• 2 big shallots, finely chopped
• 1 1/2 cup of Don de Dieu beer from Unibroue
• 1 tablespoon “herbes salées du Bas-du-Fleuve”
• 2 cups strong cheddar, grated
• 2 cups swiss cheese, grated
• 2 cups fresh parmesan, grated
• 1 1/2 cup hot milk
• 1 tablespoon cornstarch diluted in 100ml cold water
• The leaves of 5 sprigs fresh thyme
• 275g mascarpone cheese
• 10 thin slices of pancetta finely chopped, cooked in the oven on parchemin paper until crispy ( about 10 min )
• Ground pepper