Prepare the oven: Preheat your oven to 425°F and line a large rimmed sheet pan with parchment paper to prevent sticking and make cleanup easier.

Start the potatoes: Place the potato chunks directly on the sheet pan, drizzle them with 1 tablespoon of olive oil, and sprinkle with a half-teaspoon of salt and a pinch of pepper.

Toss the potatoes on the pan until they are evenly coated, then spread them out so they are in a single layer with space between the pieces.

Slide the sheet pan into the oven and roast the potatoes for 15 minutes to give them a head start on cooking.

Season the chicken: While the potatoes roast, pat the chicken thighs dry with paper towels. Rub them with 1 tablespoon of olive oil, the dried oregano, and a half-teaspoon each of salt and pepper.

Place the chicken thighs in the center of the pan, skin-side up, and scatter the smashed garlic cloves and cherry tomatoes into the spaces around the chicken and potatoes.

Finish and serve: Remove the pan from the oven and squeeze the juice from half the lemon over the hot chicken and vegetables. Sprinkle with fresh parsley and serve immediately.