Add all of the ingredients: pecans, flour, kosher salt, sugar, cold butter, and pulse until the pecans are crushed into smaller pieces.
Add the ice-cold water to the processor 1 tbsp at a time while processing on low. Process until a large ball of dough forms.
Wrap the dough in plastic wrap and refrigerate for 10 minutes. While the dough is chilling, let's make the plum filling.
MAKE THE PLUM FILLING
In a large skillet over medium-low heat, add the sliced plums, cinnamon stick, sugar, vanilla, corn starch, and kosher salt. Mix and stir until all of the ingredients have meshed together and the plums have a shiny coating of plum sauce, about 10-15 minutes.
PUTTING IT ALL TOGETHER
Preheat the oven to 375 °F.
Beat one egg and set aside.
Dust flour on a hard surface, and a rolling pin. Roll out the dough into a large circle (about 18 inches in diameter). It's ok if the edges are rustic and your circle isn't perfect. The handmade look is completely ideal for this dessert.
After the circle is created, transfer it to a baking sheet (lined with parchment paper optional as long as you have a good nonstick pan).
Transfer the plum filling right into the center avoiding the edges. Fold and shape the sides with your hands creating that beautiful galette look.
Brush the edges with egg. Sprinkle on cane sugar. Transfer the galette to the preheated oven and bake for 25-30 minutes or until golden brown.
Cooldown to room temperature before slicing.
Enjoy with company!
Notes
How to make ice-cold water? I like to add a few ice cubes into a cup of room-temp water. Another way is to put a cup of water into the freezer for 20 minutes.Don't have plums? Use peaches, apples, pears, or even strawberries instead.Don't have pecans? Use sliced almonds, walnuts, or cashews instead.Don't have any eggs? Brush the crust with melted butter.