Bring water to boil in a large pot and salt liberally. Add beans and boil until just tender . Drain beans and thoroughly rinse well under cold water. Melt butter over medium-low heat heat in a large, straight-sided skillet, stir in shallots and salt liberally. Cook until shallots are very soft and aromatic, about five minutes, then add beans. Stir to coat beans with butter and cook for one minute, then add Parmesan, and stir until Parmesan melts. Remove from heat and stir in dill. Add salt to taste and lemon juice if desired. Serve immediately.
