Place dry ingredients in food processor, pulsing briefly to mix: coconut flour, flax seed meal, gelatin and sea salt.
Add coconut oil and honey on top of dry ingredients. Pulse until dough comes together in clumps. Refrigerate 10 minutes.
With two hands, separate dough into 4 equal pieces, patting each one into 1/4" thickness. Use a knife or cookie cutters to achieve desired shapes. (The dough is a little fragile and sticky, but not terribly. Just piece it together again if two pieces separate. It really gets beautiful when baked. You can create shapes on whatever surface is easy for you: a plate, open counter, cutting board, parchment paper etc.)
Remove hot, roasted rhubarb from the oven. Reduce oven temperature to 375 degrees. Stir gelatin water and honey into roasted rhubarb, using two spoons. Top with pastry shapes. Bake until pastry is golden brown and rhubarb is bubbly, about 15 minutes.
Serve warm or chilled. If you can wait, this cobbler is really yummy chilled. The gelatin sets up both the rhubarb goo and the crust, making the texture of both ideal.