Make the dough
In a large bowl, whisk the flour with ¾ tsp each of salt and pepper. Working over the bowl, grate the frozen butter on the large holes of a box grater. Gently toss the grated butter in the flour. Stir in ⅓ cup of ice water until the dough is evenly moistened. Scrape out onto a work surface, gather up any crumbs and knead gently just until the dough comes together. Pat into a disk, wrap in plastic and refrigerate until chilled, about 1 hour.
Meanwhile, make the filling
In a large bowl, toss the asparagus with the olive oil; season with the Herbes de Provence salt and pepper, tossing well to evenly coat.
Set the oven temperature to 425°. On a lightly floured work surface, roll out the dough to a 14-inch round. Carefully transfer to a parchment paper–lined baking sheet.
Spread the softened goat cheese evenly across the bottom of the pastry crust. Follow with the layer of the onion and then the shredded Gruyere. Arrange the asparagus across the top. Fold the pastry edge up and over the vegetables to create a 1 ½-inch border.
Bake the asparagus galette for 30 to 35 minutes, until the crust is browned; let cool slightly. Sprinkle with shredded cheese, cut into wedges and serve warm.
Make ahead: The galette can be made a few hours early and rewarmed before serving
Healthy On You Recipes and cooking tips by Samantha Binkley. Many of these recipes use Samantha's 100% Organic Spice Blends that take the guess work out of cooking.