In a large bowl, mix flour and salt; cut in shortening until crumbly. Gradually add milk, tossing with a fork until dough holds together when pressed. Shape into a disk; wrap in plastic. Refrigerate for 30 minutes or overnight.
On a lightly floured surface, roll dough to 1/8-in. thickness. Using a floured 2-1/2-in. heart-shaped or round cutter, cut 18 shapes. Place 1 in. apart on ungreased baking sheets. Bake at 425° for 8-11 minutes or until golden brown. Cool on a wire rack.
For soup, heat butter in a Dutch oven over medium-high heat. Add the potatoes, onion, celery and carrots; cook and stir for 5-7 minutes or until onion is tender.
Stir in the flour, salt and pepper until blended; gradually whisk in broth. Bring to a boil over medium-high heat, stirring occasionally. Reduce heat; simmer, uncovered, for 8-10 minutes or until potatoes are tender. Stir in remaining ingredients; heat through. Serve with pastries.