In the bowl of a food processor fitted with a blade, combine flour, sugar, and salt. Pulse in the butter until the pieces are as small as breadcrumbs. Add the egg yolk and 2 teaspoons water. Add up to 2 teaspoons more water if needed to bring the dough together. On a lightly floured surface, form the dough into a disk, wrap in plastic, and refrigerate for 30 minutes.
Preheat oven to 375 degrees Lightly grease 6 (4 inch) tartlet pans.
On a lightly floured surface, roll the dough until it is 1/8 inch thick. Cut the dough and line the prepared tartlet pans. Place in refrigerator for 20 minutes. Line the top of the dough in each tartlet pan with parchment and fill with pie weights, dried beans, or uncooked rice. Bake in preheated oven until golden, 15-20 minutes. Remove from pans and cool on wire rack.
To make the cream, whisk together egg yolks and 1/8 cup sugar in small bowl. Once light yellow, whisk in cornstarch and cardamom.
In a medium saucepan, whisk together milk, remaining 1/8 cup sugar, and scrapings from vanilla bean. Bring the mixture just to a boil. Add 1/4 cup of the hot milk, a tablespoon at a time, to the eggs, whisking constantly. Pour the heated eggs into the saucepan, whisking constantly. Bring the liquid to a boil over medium heat and cook for 2 minutes, stirring continuously. Remove from heat and stir in butter. Pour into a medium bowl and cover with plastic wrap, making sure the wrap is touching the top of the cream. Refrigerate until chilled.
Fill each tartlet with cream and top with freshly sliced strawberries.
Serve immediately or chilled.