Place a rack in the upper third of the oven and heat to 400 degrees F.
Chop the dried pineapple until they are cut into small pieces, diced.
Chop the shallot into small pieces, diced
Slice the tenderloin down the middle lengthwise, creating 2 separate pieces. Lay the tenderloin pieces next to each other but at opposite ends, so when laid together they are the same size at the ends.
Lay out a 12 x 16 inch piece of parchment paper on the counter and arrange the pieces of prosciutto in the center, overlapping them enough to create a solid layer that is as long as the tenderloin. Top with a second piece of parchment, and using a rolling pin or other heavy round item, roll over the prosciutto to help adhere the pieces together.
Remove the parchment paper and sprinkle the prosciutto with salt, pepper and thyme.
Set the tenderloin down the middle of the prosciutto. Spread the dried pineapple and shallots between the 2 pieces of tenderloin and push back together. Using the parchment paper to help, wrap the prosciutto around the tenderloin to completely enclose the tenderloin.
Sprinkle the counter with flour and roll out the pastry to 12 x 14 inches. Spread the mustard thinly in the center of the pastry and lay the prosciutto wrapped tenderloin in the center of the pastry on the mustard.
Fold the puff pastry up and over the tenderloin, then roll to completely enclose, brushing the edges of the pastry with the egg wash in order to seal it closed. Brush the entire pastry with the egg wash.
Place the tenderloin wrapped pastry on a parchment lined baking sheet and bake for 30 minutes or until the pork reaches an internal temperature of 140 degrees F and the the outside is golden brown.
Remove the tenderloin from the oven and transfer to a cooling rack and let rest for 5 minutes before slicing and serving.