Preheat the oven to 225°. Line two baking sheets with nonstick baking mats or parchment paper. Using a small spoon, remove and discard pineapple "eyes". Use a sharp knife to cut pineapple crosswise into very thin slices. Place slices on baking sheets. Bake until completely dried, 25 to 30 minutes (or longer, depending on their thickness). Pinch center of each pineapple slice to shape into a cone; let cool in a clean muffin tin to form flower. Once cool, flowers can be stored (stacked) up to 3 days at room temperature in an airtight container.