Quarter potatoes. Bring a medium pot with potatoes covered by water to a boil. Cook until fork-tender, 15-18 minutes. While potatoes cook, trim and thinly slice green onions on an angle, keeping white and green portions separate. Peel, trim, and cut carrot into ¼" slices on an angle. Pat mahi-mahi dry and halve. Season both sides with ¼ tsp. salt and a pinch of pepper.

Place carrot slices on prepared baking sheet and toss with 2 tsp. olive oil, half the garlic salt (reserve remaining for potatoes), and a pinch of pepper. Massage oil and seasoning into carrot slices Spread into a single layer and roast in hot oven until fork-tender, 15-17 minutes. While carrot slices roast, finish potatoes.

Drain cooked potatoes in a colander and return to pot. Add butter, sour cream, green portions of green onions, remaining garlic salt, ¼ tsp. salt, and a pinch of pepper. Mash until mostly smooth. Cover and set aside.

Place a medium non-stick pan over medium heat and add 1 tsp. olive oil. Add mahi-mahi to hot pan and cook until fish reaches a minimum internal temperature of 145 degrees, 3-5 minutes per side. Remove mahi-mahi to a plate and tent with foil. Reserve pan; no need to wipe pan clean.

Return pan used to cook mahi-mahi to medium heat and add 1 tsp. olive oil. Add white portions of green onions to hot pan and cook, 1 minute. Add peppercorns, ¼ cup water, mirepoix base, and cheese spread. Stir often until cheese spread is incorporated and sauce is thickened, 2-3 minutes. Remove from burner. Plate dish as pictured on front of card, topping mahi-mahi with sauce. Bon appétit!