On parchment paper, roll out the Puff Pastry to about a 16 x 12 rectangle. Cut the rectangle lengthwise in half.

On each rectangle, spread the Mustard in a thin layer, then sprinkle Cheese evenly (it doesn't matter if it's to the edge of the puff pastry).

On the long side, roll the filled Puff Pastry to the center, repeat with the other edge rolling to the center until they meet in the middle. Wrap in plastic wrap securely, and place in the freezer for 10 - 15 minutes.

Preheat oven to 400°F. Line baking sheet with parchment paper.

Remove the Puff Pastries from the freezer and cut into 3/4 inch slices, and place on baking sheet about 1 inch apart.

Bake for approximately 15 - 18 minutes or until crispy and golden brown.

Best served warm or at room temperature and served same day as made.