Bring 3/4 cup water and butter to a boil in a large saucepan; reduce heat to low.
Add flour and salt; beat with a wooden spoon until mixture leaves sides of pan. Remove from heat; cool slightly.
Add eggs, 1 at a time, beating until smooth. Drop batter by 2 rounded tablespoonfuls 3 inches apart on lightly greased baking sheets.
Bake at 450° for 10 minutes; reduce temperature to 325°, and bake 15 more minutes or until golden.
Pierce cream puffs with a fork to let steam escape, and cool.
Thaw escalloped apples in microwave at MEDIUM (50% power) 6 to 7 minutes. Stir together apples, blueberries, and lemon juice.
Split cream puffs in half; fill with ice cream, top with apple mixture, and replace pastry top. Garnish, if desired.