Step 1

Line a baking sheet with parchment paper.

Step 2

In the bowl of a food processor fitted with the steel blade, process the almonds until finely chopped, about 1 minute. Transfer the almonds to a small bowl and set aside.

Step 3

Make the crust: To the bowl of the food processor (no need to clean it), add the flour, salt and sugar. Pulse briefly to combine. Add the cold butter and process just until the butter is the size of peas, about 5 seconds. Sprinkle the cold water over the mixture and process until just moistened and very crumbly, about 5 seconds.

Step 4

Transfer the dough to a lightly floured work surface and knead a few times, just until it comes together into a cohesive ball. Pat the dough into a disk. Flour your work surface again and dust the dough with flour, as well. Using a rolling pin, roll into a circle 8 to 10 inches in diameter, turning and adding more flour as necessary so the dough doesn’t stick. Transfer the dough to the parchment-lined baking sheet and refrigerate while you prepare the plums (you’ll roll the dough out further on the parchment paper so go ahead and clean your work surface).

Step 5

Assemble the galette: Cut the plums into 1/4-in-thick slices. Take the dough from the fridge and slide the parchment paper onto the countertop. Roll the dough, directly on the parchment paper, into a 13-in circle about 1/8-in thick. It’s fine if the edges are a little ragged. Place the parchment and dough back on the baking sheet – the dough will run up the lip of the sheet slightly.

Step 6

Sprinkle the flour evenly over the pastry, leaving a 1-in border. Sprinkle the chopped almonds evenly over the flour, followed by 1/4 cup of the granulated sugar. Arrange the plum slices on top in overlapping concentric circles to within about 2-1/2 in of the edge. Don’t worry about making it look perfect; it doesn’t make much difference in the end and you don’t want the dough to get too warm. Sprinkle the remaining 1/3 cup sugar over the plums.

Step 7

Fold the edges of the dough over the plums in a free-form fashion, working your way around and creating pleats as you go. Patch up any tears by pinching a bit of dough from the edge.

Step 8

Using a pastry brush, brush the pleated dough evenly with the beaten egg. Sprinkle the turbinado sugar over the top of the crust. Chill the assembled galette in the fridge for 15 to 20 minutes.

Step 9

Meanwhile, preheat the oven to 350°F and set an oven rack in the center position.

Step 10

Bake for 55 to 65 minutes, or until the plums are tender and the crust is golden brown. (It’s okay if some of the juices leak from the tart onto the pan. The juices will burn on the pan but the galette should be fine -- just scrape any burnt bits away from the galette once it’s baked.) Transfer the pan to a rack and let cool.

Step 11

While the galette cools, make the optional glaze. Place the apricot jam in a small, microwave-safe bowl and microwave until bubbling, 10 to 20 seconds. Using a pastry brush, brush the plums with the jam until glistening.

Step 12

Use two large spatulas to transfer the galette to a serving plate or cutting board. Slice and serve warm or at room temperature. The galette is best served on the day it is made, but leftovers will keep nicely, loosely covered on the countertop, for a few days.

Step 13

Make-Ahead Instructions: The dough can be made up to 3 days in advance and refrigerated. Allow it to sit at room temperature for about 15 minutes or until pliable before rolling.

Step 14

Freezer-Friendly Instructions: The assembled tart may be frozen for up to 3 months. To freeze, place the baking sheet in the freezer until the tart is frozen, then wrap tightly. Bake directly from the freezer. (It may take a few extra minutes to bake from frozen.)