Place a rack in the center of the oven and preheat the oven to 375°F. While the oven is heating up, whisk together 1 egg with 1 Tbsp water. Once the dough has risen for the second time and the crown is about 1.5 times its original size, brush the egg wash over the surface of the bread. Bake about 35-40 minutes until risen and a rich golden brown. With the egg wash, the dough may brown a bit quicker in the oven than it cooks–I usually tent the couronne with a piece of foil after the first 25 minutes of baking. The outer edges of the bread will be firm and crusty; depending on the amount of wet filling inside, the inside of the circle will be a bit softer to the touch once it reaches a golden brown, this will firm up as it cools. If you have an instant read thermometer, you can insert it into the bread to test for doneness–if the bread reads 200°F, it’s ready to come out of the oven. If ever in doubt, allow to bake for an extra couple of minutes.