Combine 5 cups water, stock concentrates, and a large pinch of salt in a medium pot. Bring to a boil. Once boiling, reduce heat to low. Halve, peel, and finely dice onion.

Heat a large drizzle of olive oil in a large pan over medium-high heat. Add onion and cook, stirring, until softened, 2-3 minutes. Add rice and 1 TBSP plain butter. Cook, stirring, until rice is translucent, 1-2 minutes. Reduce heat to medium.

Add stock, 1/2 cup at a time, stirring after each addition. Allow rice to absorb most of the liquid before adding more. Continue until rice is al dente and creamy, about 30 minutes.

While risotto cooks, wash and dry all produce. Trim and discard bottom 2 inches from asparagus. Cut off asparagus tips, then cut stalks on an angle into bite-sized pieces (about 1 inch long). Dice tomato into 1/2-inch pieces.

When risotto has cooked about 25 minutes, add tomato and asparagus to pan. Cook, stirring, until veggies have softened, 5-7 minutes.

Stir garlic herb butter and half the Parmesan into risotto. Season with salt and pepper. Divide risotto between plates and sprinkle with remaining Parmesan. Garnish with chili flakes if desired.