Wash and dry all produce. Preheat oven to 400 degrees. In a small pot, bring stock concentrate and 4 cups water to a simmer over low heat. Halve, peel, and finely dice onion. Cut zucchini into 1/2-inch cubes. Mince or grate garlic. Zest and halve lemon.

Toss zucchini on a baking sheet with a drizzle of olive oil and a pinch of salt and pepper. Roast until lightly browned, about 20 minutes, tossing halfway through.

Meanwhile, heat 1 TBSP butter in a large pan over medium heat. Add onion and garlic and cook until softened, 5-6 minutes, tossing occasionally. Season with salt and pepper. Add rice and toss until grains are translucent, 1-2 minutes. Add entire bunch of thyme to pan.

Add stock to pan 1/4 cup at a time, stirring after each addition. Allow rice to absorb stock before adding more. Continue until rice is nearly al dente, about 25 minutes—risotto should be thick but not stiff and grains should have a little bite to them. Discard thyme stems (some leaves will have fallen off).

Stir in shrimp and Parmesan. Cook until shrimp is completely opaque, 4-5 minutes. Stir in 1/2 tsp lemon zest and a squeeze of lemon. Season with salt and pepper.

Divide risotto between bowls and top with a mound of zucchini.