Thinly slice 3 large carrots and put in a bowl; set aside. Toast 1/2 teaspoon each ground cumin and sweet paprika and a pinch each of cinnamon and cayenne in a dry skillet over medium-low heat, stirring, until fragrant, 1 minute. Swirl in 2 tablespoons olive oil, then swirl in 1 tablespoon lemon juice. When it bubbles, add 1 grated small garlic clove and cook, swirling the pan, 15 to 20 seconds. Pour the hot dressing over the carrots and toss. Add 1/4 cup chopped parsley, season with salt and pepper and toss. Serve with harissa, if desired.