This fluffy loaf lives somewhere between bread and dessert, which is why it makes the best breakfast food. We started our brioche dough with a stand mixer, then rolled and shaped it by hand into a cylindrical form. This recipe’s ultimate success, however, comes down to two key things: First, the egg must be at room temperature to ensure the texture of the pistachio filling holds; second, once shaped, the dough must be placed seam-side down so the filling stays inside.