Wash and dry all produce. Adjust rack to middle position and preheat oven to 350 degrees. Peel potatoes, then cut into 1/2-inch cubes. Place in a medium pot with a pinch of salt and enough water to cover by 1 inch. Bring to a boil and cook until easily pierced by a knife, about 12 minutes. Drain, then return to pot.

Spread out hazelnuts on a baking sheet. Toast in oven until golden brown, 5-8 minutes. (TIP: Keep an eye on them— they can burn easily.) Transfer to a plate to cool, then roughly chop.

Meanwhile, halve, peel, and mince shallot until you have 2 TBSP. Halve tomatoes. Mince chives until you have 1/4 cup. Cut lemon into wedges. After returning potatoes to pot, mash with a potato masher or fork. Stir in 1/2 cup milk. Season with salt and pepper. TIP: Add more milk, if needed, to achieve a creamy consistency.

Heat a large drizzle of oil in a medium pan over medium-high heat. Pat scallops dry with a paper towel, then season all over with salt and pepper. Add to pan and cook until browned and just firm, 3-5 minutes per side. Remove from pan and set aside, covered, to keep warm.

Reduce heat under pan to medium. Add a drizzle of oil and 1 TBSP butter and allow butter to melt. Add minced shallot and tomatoes. Season with salt and pepper. Cook, tossing, until shallot is translucent and tomato is softened, 3-5 minutes. Stir in 1 TBSP vinegar (we sent more) and half the minced chives. Cook until chives have just started to wilt, about 30 seconds more. Remove pan from heat.

Divide mashed potatoes between plates. Top with scallops, then spoon shallot and tomato mixture over top. Sprinkle with hazelnuts and remaining minced chives. Serve with lemon wedges on the side for squeezing over.