Parboil: Bring a large pot of water to a boil. Cut sweet potatoes and white potatoes in half, width wise, then drop into the boiling water. Boil for 5 minutes, then remove. Drop whole beets and carrots into the boiling water and cook for 5 minutes.
Cut: Cut the potatoes into ½ inch thick (1 cm) slabs. With a small paring knife or with a cookie cutter, cut jac-o-lantern shapes into the sweet potatoes. Do the same for the white potatoes, cutting them into ghost shapes (I used a straw to cut out the eyes!) Cut beets them into ½ inch thick slabs, then cut out witch’s hat shapes. We’ll call the carrots witch’s fingers and just leave them be.
Bake: Preheat oven to 400 degrees F (204 C). Set veggies on a parchment-lined baking sheet. Drizzle with oil, sprinkle with salt, pepper, and rosemary leaves, and toss to evenly coat. Crush garlic cloves with the flat part of your knife and scatter around the pan. Bake for 1 hour, flipping the vegetables halfway through. When you have 10 minutes left, drizzle balsamic over the beets and honey over the carrots, then return to the oven.