Place the all-purpose flour, pistachios, and salt in a large bowl. Add the butter and then use your fingers to break the butter into the flour until the mixture is the size of small peas. Add 3 tablespoons cold water and mix with a spatula, drizzling in more water as needed (no more than 1 tablespoon at a time), until the dough just comes together (a few dry spots are ok). Gently knead the dough on a lightly floured surface until no dry spots remain, about 1 minute. At this point you can cover the dough and place it in the fridge while you prepare the filling, or for up to one week.In a medium bowl, combine the strawberries, honey, cornstarch, thyme (if using), and vanilla. Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper. On a lightly floured surface, roll the dough out into a rectangle or circle about 1/4 inch thick.  Transfer to the prepared baking sheet. Spread the dough with jam, leaving a 1-inch border around the edge. Arrange the fruit over the dough in an even layer. Pour any remaining juices left in the bowl over the fruit. Fold the edges up and over the berries. Brush the edges of the dough with egg and sprinkle with sugar. Place the galette in the fridge for 15-30 minutes to chill. Transfer to the oven and bake for 45-50 minutes or until golden brown. It's OK if the edges get dark. Let cool slightly and serve topped with fresh thyme, if desired, and ice cream. Enjoy!