Prep the ham: remove ham from refrigerator 45 minutes before cooking to come to room temperature. Preheat oven to 325F. Place ham cut-side down in a roasting pan. Using a sharp knife, score the surface of the ham in a diamond pattern - cuts approximately ½ inch deep and 1 inch apart. The scoring allows the glaze to penetrate and creates more surface area for caramelization.
Make the glaze: combine all glaze ingredients in a small saucepan over medium heat. Whisk together and bring to a gentle simmer. Cook 3-4 minutes until slightly thickened - it will thicken further on the ham in the oven. Remove from heat. Reserve half the glaze in a small pitcher for the table.
First glaze: brush or spoon half of the remaining glaze generously over the entire scored surface of the ham, working the glaze into the score marks. Place pineapple rings on the surface of the ham and secure each one with 2-3 whole cloves pressed through the ring into the ham.
Roast: tent the roasting pan with aluminum foil and roast at 325F. Calculate approximately 15-18 minutes per pound - a 4 lb ham will take approximately 60-70 minutes to this stage.
Second glaze and finish: remove foil, brush remaining working glaze over the ham and pineapple rings. Return to oven uncovered and increase temperature to 400F. Roast an additional 20-25 minutes until the glaze is deep amber and caramelized and the internal temperature reads 140F. Watch carefully during this phase - allulose can darken quickly.
Rest: remove from oven and rest uncovered 10-15 minutes before slicing. The glaze will set slightly during resting.
Slice and serve: carve the ham at the table alongside the warm reserved glaze for drizzling. Serve pineapple rings alongside - they have caramelized in the oven and are extraordinary.