On a large piece of parchment paper, roll the dough into a large circle, about ⅛-inch thick.
Sprinkle 3 tablespoons of breadcrumbs over most of the dough circle, leaving 2 inches without along the perimeter.
Add all of the filling mixture into the center of the dough, leaving the 2-inch perimeter empty.
Decorate the top of the filling section with sliced heirloom tomatoes. I used 4 slices total.
Once the center of the dough is filled, brush the 2-inch empty perimeter with water.
Use the parchment paper to help fold the sides of the dough in towards the center and secure by pinching the connected areas together. Do this around the circle of dough.
Refrigerate for at least 30 minutes while the oven preheats to 400°F.
Before baking, brush the dough rim with egg wash.
Bake for 35-45 minutes. *If the dough looks dry, brush it with melted butter at the 35 minute mark.
After about 30 minutes, remove the galette from the oven and drizzle with more olive oil for added shine. Bake for an additional 5-10 minutes.
Allow to cool for 10 minutes before serving!