Although we've never made this recipe from Lee Bailey's Country Weekends (Clarkson N. Potter, 1983), we do enjoy it when Merry's daughter, Nicci, makes it for us.
Preheat oven to 350 degrees. Lightly grease a cookie sheet.
Combine flour, sugar and a pinch of salt in a food processor fitted with a steel blade. Add the frozen butter and Crisco. Process until the shortening is the size of small peas. Add 5 TBS ice water. Process until dough begins to form a ball but remove before it does. (Add additional water if necessary). Gather dough into a ball, dust with flour and refrigerate in plastic wrap for 30 minutes.
Roll out half the dough into a thin sheet. Have ready the marmalade mixed with the soft buttered bread crumbs. Cut dough into 5 inch squares, place one heaping tablespoon of marmalade mixture on one side of square and fold the dough over on itself. Seal the three open sides by pressing them together with the tines of a fork. Repeat with remaining dough and marmalade. Bake until golden brown, about 20-25 minutes. Cool on rack. 8-10 tarts.