Warm the milk. Dissolve the yeast in the milk, whisking it in a bowl. Let it rest for 5 minutes, then whisk again. Sift the flour and make a well, pour the milk with the yeast into it, and mix everything together. Let it rest for 15 minutes at room temperature.
Add the sugar, salt, egg yolk, and soft butter. Knead well until you obtain a firm and homogeneous dough. Cover it with a clean cloth and let it rise for 1 hour in an oven preheated to 122°F (50°C), then turned off and closed.
Divide the dough into 6 equal portions. Roll them out with a rolling pin to form discs 0.8 to 1.2 inches (2 to 3 cm) thick. Place them on a baking sheet lined with parchment paper, spacing them well.
Whip the white almond paste with the vanilla sugar. Wash and hull the strawberries before slicing them. Place the almond paste mixture in the center of each dough disc. Top with sliced strawberries.
Brush the edges of the dough with a bit of milk using a pastry brush and sprinkle everything with sliced almonds. Bake for 30 to 35 minutes until the tartlets are well risen. Let them cool after removing them from the oven.