Adjust rack to top position and preheat oven to 425 degrees. Wash and dry produce.

Trim, peel, and halve carrots lengthwise; slice into ½-inch-thick half moons. Halve, peel, and cut onion into ½-inch-thick wedges.

Toss carrots and onion on a baking sheet with a drizzle of oil, half the cumin (all for 4 servings), and a pinch of salt and pepper. Roast on the top rack until tender, 18-20 minutes.

While veggies roast, heat a drizzle of oil in a small pot over medium-high heat. Add couscous and half the garlic powder (all for 4 servings); cook, stirring frequently, until garlic powder is fragrant and couscous is lightly toasted, 1-2 minutes.

Stir in 1 cup water (2 cups for 4 servings) and a big pinch of salt. Bring to a boil, then cover and reduce heat to low. Cook until couscous is tender, 6-8 minutes.

Keep covered off heat until ready to serve.

While couscous cooks, halve tomatoes and roughly chop pistachios.

In a large bowl, whisk half the vinegar, 2 TBSP olive oil, 1 tsp salt, and ½ tsp sugar until sugar is dissolved (all the vinegar, 4 TBSP olive oil, 2 tsp salt, and 1 tsp sugar for 4 servings). Add tomatoes and toss until thoroughly coated.

Once veggies are roasted and couscous is cooked, stir into bowl with marinated tomatoes; add spinach and toss until spinach is slightly wilted.

Divide spinach salad between bowls and top with feta and pistachios. Serve.