Preheat oven to 375 degrees F (190 degrees C). Line a baking sheet with parchment paper.

Dust a flat work surface lightly with flour. Unroll puff pastry and roll out to a rectangle. Spread with mustard and cover with Cheddar cheese slices, leaving a 1-inch border. Add a layer of ham slices on top. Roll puff pastry up tightly like a jelly roll.

Slice puff pastry roll in 1/4-inch-thick slices and lay on the prepared baking sheet.

Bake in the preheated oven on the center rack until lightly browned and puffed up, 15 to 20 minutes.