I love making tarts. It's been way too long. This is the easiest of recipes and it is really good. The tartness of the plums perfectly counterbalances the pure sugar/fat goodness of the pastry.
I always use pre made pastry dough. Just thaw, unroll and thin slightly with a rolling pin. I work right on top of the parchment paper and then just lift it all onto the baking sheet to go into the oven. Slice the plums (you can see a Santa Rosa plum got mixed up in there), lay them out and sprinkle with sugar (not too much -about 2 teaspoons). Bake at 375 degrees for about 45 minutes or until the pastry is nicely toasted. Don't worry if it's still a little runny when you take it out, it will congeal into some wicked goodness when it cools.