Line a large cookie sheet with parchment paper or a silicone mat
On a clean, lightly floured surface, roll the dough into a large rectangle about 9 x 13 inches, 1/4 to 1/2 inch thick.
Evenly spread the chopped onion over the rectangle, followed by the shredded cheese. Make sure to cover the dough all the way to the edges.
Lay the sliced ham on top, cutting the slices as needed to ensure even coverage.
Starting on the long side closest to you, tightly roll the dough into a log. Pinch the edges to seal.
Using a bench scraper or serrated knife, cut the log into 12 even rolls. First, cut the log in half, then cut each half in half again, and finally cut each section into thirds.
Place each roll on the prepared cookie sheet. Tuck any loose ends underneath. Cover with a towel and let the rolls rest while preheating the oven, or for about 20 minutes.