In the mixer bowl, dissolve the yeast in the warm milk.
Add the remaining ingredients and mix, using the hook attachment, at medium speed for 7 to 10 minutes.
The dough should be smooth and elastic to the touch.
Cover the bowl with plastic wrap and let it rise in a warm, dry place for 30 to 40 minutes. The dough should have doubled in size.

Punch down the dough, then give it a turn by lifting it from the sides and bringing it back to the center.
Cover the bowl with plastic wrap and refrigerate.
Repeat this process every 30 minutes for 2 hours.

Butter a fluted tart pan with a removable bottom.
Place the dough in the pan, cover with plastic wrap, and refrigerate for 30 minutes.

Remove the tart from the refrigerator.
Cut the plums into quarters and pit them.
Brush the tart with plum jam, then arrange the plum quarters on top, gently pressing them into the dough. Sprinkle with sugar and sliced almonds.
Let the tart sit at room temperature for 30 minutes.

Preheat the oven to 425°F (220°C).
Bake the tart for 20 minutes, then cover it with aluminum foil and continue baking for 10 to 15 minutes.
Remove the tart from the oven and let it cool for 45 minutes before serving.