Capers and butter bring a rich, savory saltiness to whatever they touch, and they are all over the delicate piece of fish in this meal. Add that acidic hit of lemon and you've got classic piccata, a lip-smacking cavalcade of deliciousness. Potato and shallot form a side of true flavor and substance.
Cut potato into ½" dice. Peel shallot and slice into ½" rounds. Place a large non-stick pan over medium-high heat. Add 2 tsp. olive oil and potato to hot pan. Cook undisturbed until browned, 4-5 minutes. Remove from burner and season with a pinch of salt and pepper.
Finish the Potato
Carefully, transfer potato and shallot to prepared baking sheet and toss with 1 tsp. olive oil. Spread into a single layer and roast until crispy and tender, 12-15 minutes. Wipe pan clean and reserve. While potatoes roast, prepare ingredients.
Prepare the Ingredients
Mince garlic. Halve and juice lemon. Stem and mince parsley. Pat sole fillets dry, and season with a pinch of salt and pepper.
Cook the Fish
Line a plate with a paper towel. Set aside 1 tsp. cornstarch. Place sole fillets on a plate and lightly rub remaining cornstarch on fish. Return pan used to cook potato to medium-high heat and add 1 Tbsp. olive oil. Add sole fillets to hot pan and cook until golden brown and fish reaches a minimum internal temperature of 145 degrees, 2-3 minutes per side. Remove to towel-lined plate.
Make the Sauce
Combine reserved cornstarch with 1 tsp. water. Place a medium non-stick pan over medium-high heat. Add 1 tsp. olive oil and garlic to hot pan and cook until aromatic, 30-60 seconds. Add ½ cup water, 2 tsp. lemon juice, and cornstarch-water mix and stir constantly, 1 minute. Bring to a simmer and cook 1-2 minutes. Remove from burner, swirl in butter, and stir in capers and parsley. Season with a pinch of salt and pepper.