Preheat your grill to medium-high heat (about 400°F/200°C). Lightly oil the grates.

Prepare the shortcake dough: In a large bowl, whisk together the flour, granulated sugar, baking powder, and salt. Cut in the cold butter using a pastry blender or your fingers until the mixture resembles coarse crumbs. Stir in 3/4 cup of heavy cream until just combined; be careful not to overmix.

Turn the dough out onto a lightly floured surface. Gently pat or roll to about 3/4-inch thickness. Use a biscuit cutter (about 3 inches) to cut out the rounds. Place them on a baking sheet lined with parchment paper, brush the tops lightly with extra heavy cream, and bake on the grill (indirect heat) or in a conventional oven at 400°F for 12-15 minutes, until golden brown.

Prepare the pineapple: Whisk together the melted coconut oil and brown sugar. Brush both sides of the pineapple slices with the mixture. Grill for 2-3 minutes per side until distinct grill marks appear and the fruit is slightly caramelized and tender.

Make the cinnamon cream: In a chilled bowl, combine the cold heavy whipping cream, powdered sugar, ground cinnamon, and vanilla extract. Beat with an electric mixer (or whisk vigorously) until stiff peaks form.

Assemble the shortcake: Split each warm shortcake biscuit horizontally. Place a grilled pineapple ring on the bottom half, top generously with the cinnamon cream, and place the biscuit top on the cream. Serve immediately, perhaps with an extra drizzle of cream.