Wash and dry all produce. Preheat oven to 450 degrees. Mince or grate garlic. Trim and discard woody bottoms from asparagus, then cut into 3-inch pieces. Strip thyme leaves from stems. Discard stems; roughly chop leaves. Put stock concentrate and 3/4 cup water in a small pot and bring to a simmer.

Toss garlic, asparagus, tomatoes, half the thyme, and a drizzle of olive oil on a baking sheet. Season with salt and pepper. Roast in oven until asparagus is tender and tomatoes have burst, about 20 minutes, tossing halfway through.

Melt 1 TBSP butter in a medium pot over medium heat. Add couscous and remaining thyme. Cook, tossing, until grains are lightly toasted, about 1 minute.

Pour stock into pot with couscous. Reduce heat to low, cover, and cook until tender, about 10 minutes total.

Meanwhile, thinly slice scallions, keeping greens and whites separate. After couscous has cooked about 5 minutes, stir scallion whites into pot. Cover and continue cooking until couscous is done, about 5 minutes more.

Fluff couscous with a fork. Season with salt and pepper. Divide between plates, then top with roasted veggies. Sprinkle with almonds, feta cheese, and scallion greens.