Combine all-purpose flour and whole-wheat flour in a food processor. Add the cold, cubed salted butter and pulse until the mixture resembles coarse breadcrumbs with pea-sized pieces of butter still visible. Add ice water a tablespoon at a time, pulsing gently until the dough just comes together—it should hold when pinched but still look shaggy. Form the dough into a disk, wrap in plastic wrap, and refrigerate for at least 1 hour. This resting time allows the gluten to relax and the butter to firm up, which creates those beautiful, flaky layers.

While the dough chills, slice the leeks into 1/4-inch rounds, keeping only the white and light green parts, and rinse thoroughly between layers to remove any sand. In a large skillet, melt 2 tablespoons butter over medium heat and add the sliced leeks with 1/2 teaspoon sea salt. Cook, stirring occasionally, for about 10 minutes until the leeks are completely softened and golden—this slow cooking sweetens them and removes excess moisture so they won't make your pastry soggy. Set aside to cool slightly.

Strain the ricotta through fine-mesh cheesecloth or a fine sieve for 15-20 minutes to remove excess whey—I find this step makes a huge difference in the final texture of the galette, preventing a watery filling. Trim the woody ends from the asparagus and set aside. Preheat your oven to 400°F while you finish the other components.

Remove the dough from the refrigerator and let it sit at room temperature for 20 minutes to soften slightly for easier rolling. Place the dough between two sheets of parchment paper and roll it into a 14-inch circle, rotating and flipping occasionally for even thickness. Transfer the dough (still on parchment) to a large baking sheet. Lightly brush the entire surface with 2 tablespoons olive oil, leaving about a 1.5-inch border uncovered—this will crisp up nicely during baking.

Spread the strained ricotta in an even layer over the oiled dough, leaving the border clear, then scatter half of the parmesan cheese over it. Arrange the cooked leeks from Step 2 and asparagus spears over the cheese in a somewhat organized pattern. Top with the remaining parmesan and 1/2 teaspoon fresh thyme. Fold the dough border up and over the filling, overlapping it slightly as you go around—it doesn't need to be perfect; rustic is the beauty of a galette. Whisk together the egg and cream or milk to make an egg wash, then brush it generously over the exposed dough edges. Bake for 35-40 minutes until the crust is deep golden brown and crispy.

Remove the galette from the oven and let it cool for 5 minutes. Tear the burrata into chunks and scatter it over the warm galette—the heat will slightly soften its creamy center. Drizzle generously with balsamic glaze, then finish with flaky sea salt and freshly ground black pepper. I like to add the burrata and glaze right after baking so the warmth of the galette releases the burrata's incredible creamy texture. Slice into wedges and serve warm or at room temperature.