1. Prepare Gluten-Free Tart Crust. Roll dough to 1/8-inch thickness on work surface dusted with brown rice flour. Cut dough into a 10-inch circle, and transfer to a baking sheet lined with parchment paper. Set aside.
2. Split vanilla bean lengthwise, and scrape out seeds. Combine vanilla seeds, blueberries, and next 5 ingredients in a bowl. Sprinkle almond flour in center of prepared dough, and spoon berry mixture on top, leaving a 2-inch border. Fold edges of dough over berry filling, pinching together to seal any cracks. Refrigerate 20 minutes.
3. Brush edges of galette with egg, and bake at 400° for 25 minutes or until filling bubbles and crust is golden brown. Let galette cool 20 minutes before cutting.
4. Serve warm or at room temperature.