Preheat the oven to 350°F. Line a baking sheet with parchment paper.
Open the croissant roll can and separate the dough into the pre-scored rectangles. Pinch the diagonal seam of each rectangle together firmly so the two triangles become one solid piece of dough.
Spread a thin, even layer of mayo and Dijon mustard over the surface of each rectangle, covering it completely.
Lay a slice of cheddar cheese over the spread, then top with a slice of ham.
Starting from the short end, roll each rectangle up tightly and place seam side down on the prepared baking sheet.
Bake at 350°F for 8 to 10 minutes until the dough is golden and cooked through. Check at 8 minutes to prevent over-browning on the bottom.
Let cool for a couple of minutes before serving.