For the syrup:

1. In a small saucepan over medium heat, combine sugar, lemon juice, and water. Bring to a boil and cook until sugar dissolves, about 3 minutes. Remove from heat and cool completely. Set aside.

For the lemon curd:

1. In a medium saucepan, whisk eggs and egg yolks together. Continue whisking while adding in sugar, lemon juice, and zest. Over medium-low heat, cook, stirring constantly with a wooden spoon, until mixture thickens and coats the back of spoon, 15–20 minutes. Do not let boil.
2. Remove from heat and stir in butter, 1 piece at a time, until smooth. Pour curd through a strainer, using the back of a spoon to help push through. Let cool to room temperature, stirring occasionally. Set aside.

For the filling:

1. In the bowl of a stand mixer with the whisk attachment, add cream and beat on high speed until stiff peaks form. Do not overbeat or cream will become butter.
2. Slice pound cake into thick 1-inch slices and lay on clean sheet pan. Using a pastry brush, brush slices on both sides with lemon syrup. Then cut slices in half or thirds.
3. Place half of cake in a glass trifle bowl or any straight-side glass bowl and spread half of whipped cream. Spread half of lemon curd on top of whipped cream and sprinkle with half of the gingersnap crumbs. Repeat layer, except for gingersnap crumbs. Chill at least 2 hours before serving. Sprinkle with remaining gingersnap crumbs before serving.