Let cheese and butter stand at room temperature about 30 minutes to soften. Stir together flour, baking powder, mustard, and salt; set aside.
In a medium mixing bowl, beat cheese and butter with an electric mixer on medium speed until well combined. Gradually add the flour mixture, beating at low speed just until combined. (Mixture will be crumbly.) Stir in almonds and chives. Add the milk, 1 tablespoon at a time, stirring until the dough clings together. Form dough into a ball, then shape it into a square log about 8 inches long and 1-1/2 inches square. Wrap the log in plastic wrap; chill for several hours.
Cut the dough into 1/4-inch-thick slices; place slices 1 inch apart on lightly greased cookie sheets. Bake in a 400 degree F oven for 7 to 9 minutes or until lightly browned on edges and bottom. Let stand about 1 minute on cookie sheets. Transfer to wire racks and cool. Store in airtight containers up to 3 days. Makes about 30 crackers.