1) For the crust, stir together flour and salt in a medium bowl. Add in butter and use fingers to work it into the flour until it is in pea-sized chunks. Add ice water and stir until just combined.
2) Turn crust out onto a lightly floured surface and knead a few times. Then roll dough into a roughly 14-inch diameter circle. Place dough on a baking sheet and stick in the fridge for 20-30 minutes.
3) For filling, chop plums in half and remove pits from each plum. Then slice plums into segments. Add plums to a colander and stir with other filling ingredients. Let drain for 15-20 minutes so extra liquid drains out.
4) When ready to bake, preheat oven to 400 degrees F. Remove dough from fridge.
5) Using a floured rolling pin and counter, roll out almond paste until it’s in a thin sheet and transfer sheet to the dough. Leave a few inches around the outer part of the dough so you can fold it over. It’s okay if the almond paste isn’t perfectly covered. This will just help the crust from getting soggy.
6) Add filling to the top of the almond paste and carefully fold edges of crust up and over filling.Try to not crack the crust.
7) Bake galette a 400 degrees F. for 50-60 minutes until crust is golden brown and filling is glazed and slightly set.
Remove galette from oven and let cool for 10-15 minutes before serving. Serve with whipped cream optionally.