Heat the oven to 425°F.

• Finely chop, press, or grate enough garlic to measure 1 teaspoon [2 tsp].

In a medium sauce pot over medium heat, warm 1 teaspoon oil until hot but not smoking. Stir in the garlic and cook until fragrant, about 1 minute. Add the couscous and ¾ cup [1½ cups] water and bring to a boil, then remove from the heat. Cover and let stand until the couscous is tender and the liquid is absorbed, 6 to 8 minutes. Fluff with a fork and cover to keep warm.
While the couscous cooks, prepare the eggplant and shrimp.

• Remove the stem from the eggplant; cut the eggplant into 2-inch pieces.
• Peel the onion and cut into ½-inch-thick slices.
• Rinse the shrimp, then drain on a paper-towel-lined plate and pat dry.

On one end of a sheet pan [on 1 sheet pan], toss the eggplant and onion with the baharat blend and 1 tablespoon [2 TBL] oil; season with salt and pepper and spread in an even layer. Roast until the vegetables start to soften, 10 to 12 minutes.
Remove the pan from the oven and stir the vegetables. On the other end of the sheet pan [on a 2nd sheet pan], carefully toss the shrimp with 1 to 2 teaspoons oil; season lightly with salt and pepper and spread in an even layer. Return the pan [both pans] to the oven and roast, turning the shrimp once halfway through, until the vegetables are tender and the shrimp are firm and cooked through, 6 to 8 minutes for regular shrimp, 8 to 10 minutes for jumbo shrimp.
While the vegetables and shrimp roast, finish the couscous.

• Strip the mint leaves from the stems; coarsely chop the leaves.

To the pot with the couscous, stir in the mint and season lightly to taste with salt and pepper.

Transfer the couscous to individual bowls and top with the vegetables and shrimp. Drizzle with as much spicy green harissa as you like and serve any remaining harissa on the side.