Combine crushed garlic, lemon juice, mustard, olive oil, and pepper, mix well. Cut a lengthwise slit down the center of the pork to within 1/2 - inch of bottom (careful not to cut all the way through).
2
Open the meat, so it lies flat. On each half, make another, lengthwise slit down the center to within 1/2 - inch bottom; cover with plastic wrap. Flatten to 1/4 - in. thickness with a mallet.
3
Remove plastic wrap; spread 1/2 of the garlic / Dijon mixture on the inside of the pork. Layer the cheese, spinach, sun dried tomatoes and prosciutto on top, press down gently.
4
Roll up pork jelly-roll style, starting with a long side. Tie the roast at 1-1/2-inch to 2-inch intervals with kitchen string.
5
Season lightly with salt, and remaining garlic/Dijon mixture. Place on a rack in a shallow baking pan. Bake, uncovered at 220C for 25-30min. or until a meat thermometer reads 70C. Let stand 10min. before removing string and slicing.