Set up grill for direct heat cooking over medium heat. If using a grid, heat that as well. Brush and oil grates (and grid) before cooking.
In a small bowl, combine spices, salt and sugar. Slice squashes in half and scoop out the seeds and then slice into 1-inch slices leaving the skin intact. Place on a baking sheet and add the sliced fennel. If you are not using a grilling grid, slice the onion into rings or slice into strips to be cooked on the grid. Toss the vegetables with olive oil and the spice mixture until slices are well-coated. Place on grill/grid and cook for 20 minutes, tuning once halfway through cooking.
Recipe by Grilling Outdoor Recipes powered by Bull Outdoor Products at https://blog.bullbbq.com/grilled-winter-squash-with-fennel-and-warming-spices/