Toast the nuts. Set a small skillet over medium heat.
Add pine nuts or chopped almonds and toast until golden and fragrant, 2–4 minutes, stirring often. Transfer to a plate to cool.
Prep the tomatoes. Rinse and halve the cherry tomatoes. If they’re extra juicy, pat them dry so the couscous doesn’t turn soggy.
Sprinkle with a pinch of salt.
Boil the liquid. In a small saucepan, bring 1 cup of water or broth to a boil. Add a pinch of salt and 1 teaspoon of olive oil.
Steam the couscous. Remove the pan from heat, stir in 1 cup couscous, cover, and let it sit for 5 minutes. Fluff with a fork to separate the grains.
Add flavor. Zest the lemon over the couscous, then squeeze in 1–2 teaspoons of lemon juice to start.
Grate in the garlic if using. Add 1/3 cup pesto and gently toss. Taste and add more pesto or lemon if needed.
Fold in the tomatoes. Add the cherry tomatoes and any juices on the cutting board.
Toss gently so the tomatoes stay intact.
Finish and serve. Drizzle with a little olive oil, season with salt and pepper, and sprinkle with toasted nuts, grated cheese, and torn basil. Serve warm or at room temperature.