Ivory "eggshells" With Lemon Cream

MAKE THE LEMON CREAM:.
Combine the eggs, sugar, lemon juice and zest in a heatproof bowl placed over, but not touching, simmering water.
Whisk continuously until thickened,8-10 minutes. Whisk in the butter, 1 tablespoon at a time. Transfer to a cool bowl and press a sheet of plastic wrap directly onto the surface to prevent a skin from forming. Refrigerate until very cold, at least 2 hours or up to 12 hours.
To complete the lemon cream, pour the cream into a chilled bowl and beat with a electric mixer at medium speed until it stars to thicken, just about 1 minute. Increase the speed to high and continue heating for 3-4 minutes or until still peaks form. Remove the plastic wrap from the lemon cream base and fold in 1/3 of the cream to loosen it up. Fold in the remaining cream into the lemon base just until no white streaks remain. Cover and chill until ready to fill the chocolate shells.
MAKE THE EGGSHELLS:.
Line a baking sheet with parchment or waxed paper. Blow up the balloon until they are approximately 4 inches high and 6 inches in diameter. Know the balloons and rinse under cool water. Dry thoroughly and set aside.
Place half (1 bag) of the chocolate morsels in a heatproof bowl over barely simmering water. Heat, stirring occasionally, until melted and smooth.
Spray 1 balloon lightly with nonstick spray. Hold the balloon by the knot and dip and roll the balloon in the melted chocolate until it is evenly coated. Hold the balloon upright over the bowl and allow any excess chocolate to drip off. Position the balloon firmly, standing upright, on the lined baking sheet and refrigerate. Repeat with the remaining balloons, melting more chocolate morsels (the second bag) as needed and immediately placing each balloon in the refrigerator. Refrigerate until the coating is very hard, at least 2 hours.
To remove the balloons, grasp a know firmly and pierce the balloon with a pin. Hang on to the know and carefully pull the deflating balloon away from the sides of the eggshell. Discard the balloon. Spoon the lemon cream into a large pastry bag fitted with a large, plain tip. Using your fingers, carefully break and pick at the edges of the shell to give it a just-cracked look. Serve immediately or refrigerate for a few hours before serving.