Cook and stir onions in butter in 1 qt saucepan over med heat for 3 min. Blend in flour, mustard, tarragon and pepper. Cook over low heat, stirring constantly, until bubbly; remove from heat. Stir in wine and chicken broth. Heat to boiling, stirring constantly. Boil and stir 1 min. Stir in bacon. Heat water (1 1/2-2") to boiling; reduce to simmer. Break each egg into measuring cup or saucer; holding cup close to water's surface slip 1 egg at a time into water. Cook until desired doneness, 3-5 min. Remove eggs with slotted spoon. Place 2 eggs on bottom half of each croissant or muffin; spoon wine mixture over eggs. Serve with top half of croissant or muffin.