How to Make It
Preheat the oven to 425°. Cut 1 inch off the top of the garlic head and place the head on a piece of foil; drizzle with 1 tablespoon of the olive oil and wrap it tightly. On a large baking sheet, toss the squash with 2 tablespoons of the olive oil and season with salt and pepper. Set the garlic on the oven rack. Roast the squash for 35 to 40 minutes, turning occasionally, until tender and golden brown. Roast the garlic for about 1 hour, until completely soft. Let cool.
Meanwhile, in a small nonstick skillet, heat the remaining 1 teaspoon of olive oil. Add the pumpkin seeds and cook, stirring, until lightly golden and starting to pop, 3 minutes. Transfer the seeds to a paper towel-lined plate and season with salt.
Scrape the roasted squash into a food processor. Squeeze the garlic cloves from their skins into the processor. Add the yogurt, tahini, lemon juice and cayenne pepper. Puree until smooth, adding a little water if the dip is too thick. Season with salt and pepper. Transfer the dip to a serving bowl and drizzle with olive oil. Top with the toasted pumpkin seeds and serve with the roasted vegetables.