A question about a recipe: Lamb Merguez Need to make some substitutions, to leave out the various capsicum ingredients.

I agree with Cathy. My ras el hanout comes out with a slightly sweet profile thanks to the cinnamon, ginger, coriander, nutmeg, allspice and mace profiles in it. I think it would make an absolutely lovely sausage, but it will taste more like a bisteeya, than a merguez, and there is nothing wrong with that! The sweet squash would be a wonderful companion, and while it may not taste like Merril's - it would be really awesome! Instead of harrisa, why not make a charmoula paste instead?
1/2 cup plus 1 tablespoon olive oil
3 large tomatoes—peeled, seeded and finely chopped
3/4 cup (packed) cilantro leaves
3/4 cup flat-leaf parsley leaves
3 tablespoons fresh lemon juice
1 tablespoon minced garlic
1 1/2 teaspoons sweet paprika
1 teaspoon ground cumin
1 teaspoon salt

I would also leave the rosemary out of the final recipe and maybe substitute some preserved lemon and toasted almonds for crunch.

Merguez is a kind of catch all name for a type of Middle Eastern sausage. As I've done more research, I've found many versions, some using ras al hanout, some using harissas with and without peppers, tomatoes - I would consider it a pretty blank canvas, ready for you to make your own. Make up a spice mixture that smells good to you and taste test little patties until you are happy. The tomato paste and some liquid will be necessary to get the right texture, and that will be the challenge without the harissa. I've made merguez now with lamb, goat and venison, and each meat requires slight adjustments to the mixture, just to balance the flavor of the meat.