Bring a medium pot of salted water to a boil. Wash and dry produce.

Trim and quarter mushrooms (skip if your mushrooms are pre-sliced!). Trim and thinly slice scallions, separating whites from greens. Dice tomato.

Rinse shrimp* under cold water, then pat dry with paper towels. Season all over with salt and pepper. Heat a large drizzle of oil in a large pan over medium-high heat. Once pan is hot, add shrimp and cook, stirring occasionally, until opaque and cooked through, 4-6 minutes. Turn off heat; transfer to a plate and cover to keep warm. Wipe out pan.

Melt 1 TBSP butter (2 TBSP for 4 servings) in a large pan over medium-high heat. Add panko; cook, stirring, until golden and toasted, 2-3 minutes.

Stir in half the garlic powder (you’ll use the rest later). Cook until just fragrant, 30 seconds. Season with salt and pepper. Turn off heat; transfer to a small bowl. Wipe out pan.

Use pan used for shrimp here.

Add penne to pot of boiling water. Cook, stirring occasionally, until al dente, 9-11 minutes. Drain.

While pasta cooks, heat a large drizzle of olive oil in same pan over medium-high heat. Stir in mushrooms and a pinch of salt. Cook, stirring occasionally, until browned and tender, 5-7 minutes. Reduce heat to medium.

Stir scallion whites, remaining garlic powder, and 1 TBSP butter (2 TBSP for 4 servings) into pan with mushrooms. Cook, stirring, until fragrant, 30 seconds.

Stir in stock concentrate, cream cheese, half the Parmesan (save the rest for serving), and ⅓ cup water (½ cup for 4). Cook, stirring, until combined and creamy, 2-3 minutes. Turn off heat.

Stir in tomato, another 1 TBSP butter (2 TBSP for 4), and truffle seasoning to taste. Season with salt and pepper.

Stir in shrimp along with tomato.

Stir drained penne into pan with sauce until thoroughly coated, adding water a splash at a time until sauce reaches a creamy consistency.

Divide between bowls; top with scallion greens and remaining Parmesan. Sprinkle with as much garlicky panko as you like and serve.