In a large bowl, mix the pumpkin puree, eggs, oil, water, and brown sugar until well blended. In a separate bowl, whisk the flour, baking soda, salt, cinnamon, nutmeg, cloves, and ginger until thoroughly combined. Stir the dry ingredients into the pumpkin mixture until just blended. Pour the mixture into the prepared pans. Bake until a toothpick inserted in the center comes out clean, about 50 minutes. Once the cake is done, decrease the oven temperature to 325Â°F. Meanwhile, in a large oven-safe sautĂŠ pan over medium heat, sear the pineapple until golden brown on both sides, about 3 minutes per side. Deglaze the pan with the bourbon, pineapple juice, and vanilla bean. Cover the pan with foil and bake until fork tender, about 40 minutes. Meanwhile, combine the cornstarch and water and mix until smooth. Set aside. (Note: This is the slurry.) Remove the pineapple, reserving the liquid, and set aside to cool. Pour the liquid into a saucepan over medium-high heat. Remove the vanilla bean pod, add the slurry, and bring to a boil until the liquid is slightly thickened and coats the back of a spoon. To serve, cut each loaf into 8 slices. Lightly butter both sides of each slice and place on a grill preheated to high; cook until the milk solids are charred, about 2 minutes per side. Serve immediately, drizzling each slice with the bourbon-braised pineapple and the sauce.