Preheat oven to 400ºF and line a medium sheet pan with parchment paper. Stir together ingredients for butter herb sauce. Place pieces of corn on the top half of the baking sheet and brush with herbed butter. Bake for 20 minutes.

Remove pan from oven and increase oven temperature to 425ºF. Blot excess moisture from shrimp with a paper towel and place shrimp on the bottom half of the pan. Add potatoes to the center of pan and drizzle remaining herb butter over shrimp and potatoes. Use hands to toss, coating potatoes and shrimp in sauce. Bake for 12 minutes longer.

Divide watercress between large compartments of 4 MPOF white containers. Divide baked shrimp evenly over watercress. Divide potatoes between one of the smaller compartments and add a piece of corn to the other small compartment.