Step 1: Preheat the grill to high. Brush and oil the grill grate.
Step 2: Cut the stem and rind off the pineapple and slice into 1/2 inch rounds. Core off each pineapple slice with a small donut hole-size cookie cutter or a small knife. Place the melted butter in one shallow bowl; mix the sugar and cinnamon in another bowl.
Step 3: Dip each slice of pineapple first in melted butter, then in the cinnamon-sugar mixture, shaking off the excess. Grill the pineapple slices until browned and sizzling, 4 to 5 minutes per side, rotating 90 degrees for crosshatched grill marks. Transfer the pineapple to plates or a platter.
Serve with Ham in a Hurry.