How to Make It
Preheat oven to 375°F. Arrange baguette slices in a single layer on a baking sheet. Brush tops with melted butter. Bake in preheated oven until slices are just beginning to brown at edges, about 12 minutes. Remove from oven, and cool to room temperature.
Spread 1 1/2 teaspoons Lemony Buttermilk Cream Cheese on each crostini.
Top with prosciutto, mustard-mayonnaise sauce, and chive sprigs.