Preheat the oven to 400°F. Prepare the tartlet shells: Lightly spray the tartlet pans with spray oil (or brush with melted butter).

Use the eggroll wrappers to line the pans, pushing the dough into the ridges in the sides. Trim off the excess with scissors. Lightly spray the insides of the tartlet shells with oil or brush with butter. Bake until crisp and golden brown, 6 to 8 minutes, or as needed. Transfer the shells to a wire rack to cool.

The tartlets can be made ahead of time, but they must be assembled at the last minute. Store the shells in an airtight container, and the filling in the refrigerator.

Meanwhile, prepare the lemon filling: Combine the sugar and cornstarch in a mixing bowl and whisk to mix. Whisk in the eggs and egg whites. Bring the lemon juice and lemon zest to a boil in a heavy saucepan. Whisk this mixture in a thin stream into the egg mixture. Return the mixture to the pan and bring to a boil, whisking steadily.

Reduce the heat and simmer for 1 minute or until thickened. Transfer the lemon mixture to a bowl and let cool to room temperature.

Not more than 5 minutes before serving, spoon the lemon filling into the crusts. Arrange the fresh raspberries on top and sprinkle the tartlets with confectioners' sugar. Serve at once.