Preheat the oven to 400 degrees Fahrenheit. While the oven is preheating, roll out the dough on a surface dusted with both flour and granulated sugar. Roll out dough until to the thickness that is about 1/8" - not too thin, but rolled out enough that you have space for your filling and a 1 1/2 -2" edge to fold over. Place the dough on a parchment lined baking sheet.
Spread the Frangipane on top of the dough, spreading evenly and leaving the outer 1 1/2 -2" edge clean and free of Frangipane as you will fold this over for the edge.
If you would like the houndstooth or chevron design, slice the ends of each slice of 3 inch rhubarb at an angle. One half of the slices will need to be sliced on the bias from left to right (tops and bottoms the same), and the other half right to left (tops and bottoms the same). However, what I did is only place the two rows in the center in a houndstooth pattern, and the outside areas, I filled with the rest of the rhubarb that had been trimmed off the middle slices as to use every bit of the rhubarb stalk. A little organized, a little rustic, a lot of scrumptious deliciousness.
Place the rhubarb on top of the Frangipane in the pattern of your choice. Sprinkle the sugar and salt on top of the rhubarb before folding. Fold the edge over the rhubarb, pulling 2-3 inches up and over at a time and at a slight angle, so that the next 2-3 inches can overlap. It will be rough and rustic, just try to seal the edges/corners so no goodness oozes out (but if it does, that is okay as well, as you have placed it on a parchment-lined baking sheet.
Brush the edges of the dough with a beaten egg and then sprinkle with 1-2 tablespoons of trubinado sugar. Bake in the oven for 30-40 minutes or until golden brown. Serve warm topped with chantilly cream and a hot cuppa.