For the curd: Whisk together the sugar and eggs in a heatproof bowl until the sugar is completely dissolved. Reserve 1 teaspoon of the lemon zest for garnish, then stir the lemon juice and remaining zest into the sugar-egg mixture. Put the bowl over a double boiler and cook, whisking, until the mixture thickens, 6 to 8 minutes. Remove from the heat and whisk in the butter. Scrape into a clean bowl and press plastic wrap directly onto the surface of the curd. Refrigerate for at least 2 hours.
For the raspberry sauce: Reserve 12 raspberries for garnish and put the rest into a small pan. Add the sugar and cook over medium-low heat, breaking up the raspberries to release their juices. Do not let boil. Strain the juice into a bowl and let cool; discard the solids.
For the tarts: Preheat the oven to 350 degrees F. Put the phyllo shells on a baking sheet and bake until lightly browned, 3 to 5 minutes. Remove the shells to a rack to cool.
To assemble the tarts: Spoon a small amount of the raspberry sauce into each tart shell. Whisk the cream with a spoonful or 2 of the raspberry sauce and a splash of vanilla. Fill each shell with the lemon curd and then top with a dollop of whipped cream and a whole raspberry. Sprinkle with some of the reserved lemon zest and add a mint leaf.