Poke holes in sweet potato and bake for 45 minutes.
Drizzle grapes with olive oil and season with salt & pepper. Arrange grapes in an even layer on a lined baking sheet. Add to oven with sweet potato, roasting for 20 minutes.
Remove sweet potato from skin and mash. Stir maple syrup and red pepper flake into mashed sweet potato. Season with salt & pepper.
Assemble crostini by layering ricotta, sweet potato mixture, caramelized onion, and topping with roasted grapes.
Recipe by Rachel Schultz at https://rachelschultz.com/2015/01/16/sweet-potato-roasted-grape-crostini/