I made this plum torte with some prune plums (quetsches) that my friend's kids picked while we were in Burgundy last month. It adapted from the famous recipe from Marion Burros that has a cult-like following. It's super-easy to make and very adaptable; I used a 9-inch (23cm) tart pan but you could use a shallow cake pan, or springform pan, or a pie tin or plate to bake it in. The original recipe noted you could use any size baking vessel, from 8" to 10" (20-25cm) in diameter.
I also used the less-generous amount of sugar recommended in the batter, and some might still find it a tad on the sweet side, so feel free to use the tartest plums you can find. You could also add a handful of raspberries or blueberries, scattered in between the plums too.
If plums aren't available where you are, try it with nectarines, apricots, or peaches. Other adaptations are here.
3/4 cup (150g) sugar, plus more for sprinkling over the tart
1/2 cup (4 ounces, 115g) butter, unsalted, at room temperature
1 cup (140g) all-purpose flour
1 teaspoon baking powder, preferably aluminum-free
Pinch of salt
2 large eggs, at room temperature
12 medium plums, or 18 to 20 small plums, halved and pitted
Freshly squeezed lemon juice
Ground cinnamon (optional)
Preheat the oven to 350ºF/180ºC. Butter a 9-inch (23cm) tart or cake pan, or pie dish.
In the bowl of a stand mixer, or by hand, beat the sugar and butter until light and creamy. In a separate bowl, stir together the flour, baking soda, and salt, then mix the dry ingredients into the butter, as well as the eggs, until smooth. (Don't overbeat.)
Spread the batter into the pan and place the plum halves, cut side down, over the batter, pressing them in lightly. Sprinkle with a bit of lemon juice, scatter additional sugar over the top, as well as some ground cinnamon, if you wish.
Bake until the batter is golden brown in the center, 50 to 60 minutes. Remove from oven. Serve warm or at room temperature, on its own, with whipped cream or ice cream, and a fruit compote, if you wish.