How to Make It
Preheat the oven to 375°. On a work surface, using the flat side of a chef's knife, mash the whole garlic clove to a paste with a pinch of salt. Scrape the garlic paste into a small bowl and stir in the tomato paste and fresh lemon juice. Add the ancho chile powder, smoked paprika, cayenne, cumin and caraway. Gradually stir in 1/4 cup plus 2 tablespoons of the olive oil and season the harissa with salt.
In a bowl, toss the butternut squash and sliced garlic with 2 tablespoons of the harissa, the remaining 2 tablespoons of olive oil and the water and season with salt and pepper. Spread the squash in a single layer in an 8-inch square baking dish. Roast in the center of the oven for 1 hour and 15 minutes, or until the squash is tender and browned in spots.