Preheat oven to 425º F. Blanch the green beans in boiling water for about 1 minute, then drain and transfer the beans to ice bath. Set aside.

In a skillet, melt the butter until foamy. Add the mushrooms and shallot. Saute until the shallot is translucent, then add the garlic and minced thyme. Season with a pinch of kosher salt and saute for another minute. Remove from heat and let cool. 

In a bowl, stir together the ricotta and goat cheese. Set aside.

On a lightly floured surface, roll the pastry dough out to about 14-inches on the long side. 

Facing a short side of the dough, create a point at the top by slicing away the top two corners of the dough. Then create a notch in the bottom side (closest to you), by cutting away a short rectangle of dough from the bottom center. Use a pizza wheel to make ~11 cuts diagonally on each side of the pastry, leaving a wide strip in the center for the toppings.

Spread the cheese mixture down the center leaving the top point free of toppings. Then spread the mushroom mixture on top of the cheese. Layer the blanched green beans on top of the mushrooms. Sprinkle the top with grated cheddar. 

Then, working from the top, side farthest from you, fold the point over the toppings, then working alternating sides, overlap the strips on the sides to create a braid. Seal up the bottom. Brush the braid with the egg and water mixture. Sprinkle with sesame seeds and bake for 15-20 minutes, until the pastry is puffed, golden, and the toppings are bubbling. 

Let cool for 5-10 minutes, then slice it how you like it!