Wash and dry all produce. Combine 4 cups water (7 cups for 4 servings) and half the stock concentrates in a medium pot; bring to a boil. Once boiling, reduce heat to low. While stock simmers, halve tomatoes. Zest and quarter lemon (quarter both lemons for 4 servings). Pick basil leaves from stems; discard stems and roughly chop leaves. Mince or grate garlic.

Heat a drizzle of oil in a large pan over medium heat. Add half the garlic and cook, stirring, until fragrant, 30 seconds. Add rice and stir until translucent, 1-2 minutes. Add 1/2 cup stock and bring mixture to a simmer. Cook, stirring, until liquid has mostly absorbed. Repeat with remaining stock, adding 1/2 cup at a time and stirring until liquid has mostly absorbed, until rice is al dente and creamy, 25-30 minutes.

Meanwhile, pat trout dry with paper towels and season all over with salt and pepper. Once risotto has cooked for 15 minutes, heat a drizzle of oil in a separate large, preferably nonstick, pan over medium heat. Add fish to pan skin side down. Cook until skin is crispy, 5-6 minutes. Flip and cook until opaque and cooked through, 4-6 minutes more. Turn off heat; transfer to a plate and wipe out pan.

Heat a drizzle of oil in same pan over medium-high heat. Add tomatoes and remaining garlic; cook, stirring, until slightly softened, 1-2 minutes. Stir in remaining stock concentrates and 1/4 cup water (1/3 cup for 4 servings). Simmer until water has mostly evaporated, 2-3 minutes. Turn off heat and stir in 1 TBSP butter and lemon juice (to taste). Season with salt and pepper.

Once risotto is al dente, turn off heat and stir in Parmesan, lemon zest, a squeeze of lemon juice, half the basil, and 1 TBSP butter (2 TBSP for 4 servings). Taste and season generously with salt and pepper.

Divide risotto between bowls and top with trout. Spoon burst tomatoes over trout and garnish with remaining basil leaves. Serve with remaining lemon wedges on the side.