Preheat oven to 400˚F.
Lay puff pastry sheets onto a clean surface, side by side and place a 10” (in diameter) bowl upside down, over each sheet and trim around the edge to create 2 even circles.
In a mixing bowl combine mascarpone, gruyere, Parmesan, chives, thyme, sage, salt, and pepper. Stir together.
Evenly spread mascarpone mixture over one of the puff pastry rounds and carefully place the other round on top.
Transfer circles to a baking sheet lined with parchment.
Place a 2.5” (in diameter) prep bowl upside down over the surface and using a sharp knife create 16 even cuts around the circle, from the center (where the prep bowl’s edge starts) to the outer edge of the circle ‘sandwich’. You should end up with something that looks like a ‘sun with rays’.
Remove the prep bowl starting from one side, grab 2 of the cut strips and twist them both outward twice before bringing the two edges together and pinching them closed.
Add 1 tablespoon water to the beaten egg and brush mixture over the whole star.
Optional step: Using a small, star shaped cookie cutter, cut a star from the center of the braided bread.
Bake braided star bread for 20 to 25 minutes or until golden brown and puffed. Allow bread to cool for about 10 minutes and serve.