How to Make It
Preheat the oven to 450°. Line a large baking sheet with parchment paper. On a lightly floured surface, roll out the dough to a 12-by-16-inch rectangle; transfer to the baking sheet. Fold the dough edge over itself to form a 1/2-inch border all around and pinch the corners together. Refrigerate until firm.
Mix the crème fraîche, garlic, hot sauce and zest; season with salt and pepper. Spread over the dough. Top with the cheese, spinach and artichokes. Brush the edges with egg wash.
Bake the galette in the bottom third of the oven for about 25 minutes, until the edges are slightly puffed. Cut into squares, garnish with sliced scallions and serve warm.