Pork rib roast in mustard and fine herbs crust - Le Coup de Grâce

Ingredients

• 1/4 cup olive oil
• 1/4 cup old mustard
• 1/4 cup Dijon mustard
• 2 tablespoons fresh thyme, finely chopped
• 2 tablespoons fresh rosemary, finely chopped
• 2 tablespoons white wine
• 3 garlic cloves, finely chopped
• 2 pork squares of 750g each
• Salt and pepper from the mill
• 2 tablespoons butter
• 2 tablespoons olive oil
• 2x 227g pack white mushrooms, sliced
• 2 tablespoons rum
• 3 tablespoons Dijon mustard
• 1 tablespoon old mustard
• 1 1/2 cup milk
• 1 teaspoon cornstarch diluted in 1 tablespoon cold water