Step 1

Preheat oven to 350° F. Grease a 9-inch springform pan with baking spray or butter and flour. If you don't have a springform pan, use a 9-inch cake pan instead. Line the bottom of the pan with a 9-inch parchment baking round. Lightly grease the parchment paper. Place the pan on a baking sheet.

Step 2

Whisk the flour, cinnamon, salt, and baking powder together in a small bowl; set aside.

Step 3

Cut the plum halves in half again and toss them in a medium bowl with the tapioca/cornstarch, brandy (see note below), and ¾ cup of the sugar; set aside for 15 minutes.

Step 4

Meanwhile, make the dough. Beat the butter and remaining sugar together until light and fluffy, about 1 minute at medium-high speed. With the mixer on low, gradually add the dry ingredients and stir just until it starts to come together. Add 1 tablespoon of the water and stir the mixture for about 30 seconds, until it becomes crumbly and just holds together when lightly squeezed. If the mixture still seems a little dry at this point, stir in another tablespoon of water.

Step 5

Reserve about 1 cup of the dough on the side and press the remaining dough into the bottom of the prepared pan in an even layer and working the dough about 1 inch up the sides of the pan. Pour the fruit mixture evenly over the dough (or neatly arrange the plums in concentric circles if you want the tart a little less "rustic"). Crumble the remaining dough over the top of the fruit.

Step 6

Bake for 55 - 65 minutes, until the fruit is bubbly and the crust is golden brown. Cool the tart for 15 minutes before running a knife around the inside edge and removing the sides of the pan.  Serve warm or at room temperature with or without ice cream. Vanilla and cinnamon vanilla bean are perfect choices here, especially if you're into making your own, though we ate ours with a local crème fraîche ice cream I found recently and we were not at all disappointed.