Step 1 Beat butter, sugar and salt in bowl until smooth by hand or in food processor, about 3 minutes.
Step 2 Add egg and yolk and mix until well-combined. Add flour and mix until evenly blended. Scrape down sides of mixing bowl several times.
Step 3Form dough into ball, flatten into disc and wrap in plastic wrap. Refrigerate at least 1 hour or overnight.
Step 4Spray 13-inch tart pan with removable bottom or 2 (8-inch) tart pans or pie tins with vegetable spray.
Step 5Roll out dough to at least 16 inches across for large tart. (For 2 standard pies or tarts, divide dough in half and roll dough 9 to 10 inches across and place in pan in same manner as for large tart.) Place dough in tart pan, and trim off excess, leaving 1/2 inch overhang. Fold overhang into side of tart pan so sides are double thick. Use scraps to make decorations for top. Bake decorations separately on baking sheet at 350 degrees 5 to 8 minutes.
Step 6Place lined tart pan in freezer while you make filling, or refrigerate at least 1 hour.