Cut the plums by scoring from the stem all the way lengthwise around the plum. However, take care to leave each fruit in one piece.

Discard the pit then turn the plum and score in the opposite direction, only halfway down

this time. Repeat until all the plums have even scored.

Grease both tart pans.

Put the flour, fresh yeast, egg yolk, salt, 1/4 cup white granulated sugar, and vanilla sugar together in a bowl.

Do not mix.

Cover the bowl and set aside for a half hour in a warm place.

Warm the milk, taking care not to boil it. Add the milk to the yeast mixture. Add the margarine or vegetable shortening, mix and knead the mixture thoroughly.

Cover the bowl once more and set aside in a warm place for 20 minutes or until the dough doubles in size.

Preheat oven to 400 Degrees F.

Split the dough in half. Roll it out into a circle and transfer to pan. Trim the edges.

Using a fork make impressions to form the crust and poke holes in the bottom.

Sprinkle one heaping tablespoon of breadcrumbs evenly over the crust in pan. This helps absorb the juice from the plums and prevents a soggy crust.

Starting from the outer edges, lay the plums on top of the crust.

Let the tart stand in a warm place for 15 minutes and then put in the oven and bake for 20 minutes.

While the first cake one is baking, prepare the second.

After removing the tart from the oven, sprinkle with a tablespoon of sugar over the top. If desired, whip some heavy cream and spoon a bit on top of each slice you serve.