Heat oven to 350°F. Lightly grease 24 small tart pans or mini muffin cups. In each tart pan, place 1 rounded teaspoon dough; gently press in bottom and up side. (Wrap and refrigerate remaining dough for another use.) Place tart pans on cookie sheet.
Bake 7 to 9 minutes or until light golden brown. Cool 1 minute; carefully remove tart shells from pans to cooling racks.
Grate peel from lemon (about 4 to 5 teaspoons); set aside. Squeeze juice from lemon, adding water if necessary to equal 1/4 cup; place in 2-quart saucepan. Stir in sugar and butter. Heat over medium heat until butter is melted. Remove from heat; stir in beaten eggs. Cook over low heat, stirring constantly, until mixture thickens. Stir in lemon peel. Cool slightly, about 15 minutes. (Lemon filling can be refrigerated at this point until ready to serve).
To serve, spoon about 1 tablespoon lemon filling into each tart shell. Garnish as desired.