Combine apricots and water in a saucepan; let stand 8 hours.
Stir in 2 1/2 cups sugar; cook over medium-high heat, stirring constantly, until mixture boils. Cover, reduce heat, and simmer, stirring occasionally, 10 minutes. Uncover and increase heat to medium-high; cook, stirring often, 8 to 10 minutes or until thickened. Remove from heat; cool slightly. Stir in extracts and, if desired, liqueur; cool.
Unfold 1 piecrust, and press out fold lines. Cut to fit into the bottom of a deep 2-quart baking dish, reserving excess pastry.
Spoon half of apricot mixture into dish; top with reserved pastry.
Bake at 475° for 12 minutes or until lightly browned. Spoon remaining apricot mixture over pastry; cool.
Unfold remaining piecrust; roll to 1/8-inch thickness, and cut into 1-inch strips. Arrange in a lattice design over apricot mixture.
Bake at 475° for 15 minutes; sprinkle with 1 tablespoon sugar and almonds, and bake 2 to 3 more minutes. Serve warm with Custard Sauce.