Cut an “X” in the core of each brussels sprout. In a Dutch oven, bring 1/2 in. of water to a boil. Add brussels sprouts; cover and cook for 8-12 minutes or until tender.
Meanwhile, in a small saucepan, saute shallots in butter until tender. Add the cream, mustard, salt, tarragon and pepper. Cook and stir over medium heat until thickened. Drain sprouts; add cream mixture and heat through. Sprinkle with cheese.