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.

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.

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 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.