Preheat oven to 400 degrees. Grease a standard muffin tin with nonstick spray.
Unfold pastry dough onto lightly floured surface. Roll with a rolling pin very gently just to iron our creases and create a perfectly flat surface. Spread top of dough with Dijon mustard. Lay thin slices of ham across the puff pastry. Then, top with slices of cheddar cheese.
Starting from the slightly longer edge, roll pastry into a log. Cut log into two halves and then cut each half into 6 even pieces. Lay each piece, cut side up, into greased individual muffin tin molds. Bake in preheated oven until pastry is puffed and golden brown, between 18-20 minutes. Let cool for 5 minutes and then serve immediately.
