Wash chard well; drain. Cut off and thinly slice the white stems. Slice the leaves separately. Place stems in a frying pan, add 2 teaspoons of the broth, cover and cook over medium heat until tender, about 4 minutes. Add the leaves and 1 more teaspoon of the broth if needed, and cook, covered until limp, about 3 minutes longer. Turn chard and remaining broth into a blender and whirl until smooth (you should have 3 to 3 1/2 cups). In a frying pan, melt butter over medium heat; add mushrooms and sauté 5 minutes. Stir in flour and curry powder; cook until bubbly. Slowly add the cream. Cook, stirring until thickened. Add chard puree and salt and pepper to taste. Garnish with the crumbled bacon. Serves 4.