Line two baking sheets with silpats or parchment paper. Set aside.
Turn the dough out onto a clean and very lightly floured surface or silicone mat. Roll it out into a rectangle that is about 12-inches by 18-inches. Scatter the olives over the surface of the dough, leaving about an inch clear of olives on the side farthest from you.
Gently lift the edge closest to you and fold away from yourself over the olives.
Continue to carefully lift and roll the dough away from you until you have a long tube. Pinch the seam closed.Use a bench knife or serrated knife to cut the dough into 16 equally-sized pieces.
Hold a piece of dough with the cut sides out. Use your thumbs to pull the top of the dough over the cut sides toward the bottom. Push that up under the roll toward the center, rotate the dough ball a half turn and repeat. Put the dough ball on the counter and cup your hand around it, rotating in one direction until the top of the dough is taut. (See the video in the blog post for an example of how to do this.) Place this on your lined baking sheets. Repeat, leaving plenty of room between the rolls for expansion in rising and baking.
Cover the rolls with a tea towel and let rise in a warm, draft-free place for about 30 minutes, or until they look a little puffy.
While they rise, use a fork to whisk a small amount of the water into the cornstarch in a microwave safe container or a small saucepan, forming a paste. Use the fork to whisk in the remaining water and microwave on HIGH for 30-60 seconds or boil until it is glassy.
Preheat the oven to 400°F. Brush the rolls with the cornstarch glaze and use a sharp knife to make three to four cuts of about 1/8-inch deep each to the top of the roll. I like to do a scallop pattern, but you could also do a tic-tac-toe pattern. This allows the roll to expand while baking without tearing that beautifully taut top you worked so hard to create.
Bake for 23-26 minutes, or until deep golden brown. Remove the pan from the oven and transfer the rolls to a wire rack to cool completely before slicing. These are good for up to three days.