For the lemon cream:
1 1/2 cups sugar
1 cup fresh lemon juice
2 tablespoons grated lemon zest
1/2 cup (1 stick) unsalted butter, at room
temperature, cut into table spoon-sized pieces
2 cups heavy cream
For the eggshells:
6 small, round balloons (size 5)
2 bags (12 ounces each) white chocolate morsels
nonstick cooking spray
For the egg yolk:
Lemon curd or lemon pie filling
To make the lemon cream, combine the eggs, sugar, lemon juice, and zest in a heatproof bowl placed over (not touching) simmering water. Whisk continuously until thickened, 8 to 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 an electric mixer at medium speed until it starts to thicken, about 1 minute. Increase the speed to high and continue beating until firm peaks form, 3 to 4 minutes. Remove the plastic wrap from the lemon cream base and fold in one-third of the cream to loosen it up. Fold the remaining cream into the lemon base just until no white streaks remain. Cover and chill until ready to fill the chocolate shells. To make the eggshells, line a baking sheet with parchment or waxed paper.
Blow the balloons up until they are approximately 4 inches high and 6 to 7 inches in diameter. Knot the balloons and rinse under cool water. Dry thoroughly. Set aside.
Place half of the chocolate morsels in a heatproof bowl over (not touching) barely simmering water. Heat, stirring occasionally, until melted and smooth.
Spray 1 balloon lightly with nonstick cooking 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 as needed and immediately placing each balloon in the refrigerator. Refrigerate until the coating is very hard, 1 to 2 hours. To remove the balloons, grasp a knot firmly and pierce the balloon with a pin. Hang on to the knot 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. Carefully pipe the lemon cream in the eggshells, filling to within 1 to 2 inches of the top.
Place a round dollop of lemon curd or lemon pie filling on the lemon cream in each cup to simulate an egg yolk (see photo). Using your fingers, carefully break and pick at the top of the shell to give it a just-cracked look. Serve immediately or refrigerate for a few hours before serving. Makes: 6 servings