Preheat oven to 450°F with a rack in the lower third. Scrub 12 oz Yukon gold potatoes, halve lengthwise, and cut into ½-inch thick wedges. Toss on a rimmed baking sheet with 1 tablespoon olive oil and a generous pinch each of kosher salt and ground pepper. Roast on lower oven rack until lightly browned underneath, 12-15 minutes.

Thinly slice 1 large garlic clove. Halve and thinly slice all of the 1 red onion lengthwise into half-moons. Pick and finely chop 1½ teaspoons of fresh oregano leaves; discard stems. Finely grate ¾ oz Parmesan. Squeeze 1 tablespoon lemon juice into a liquid measuring cup. Add 1 pkt chicken broth concentrate and ⅔ cup water to lemon juice; stir to combine. Cut any remaining lemon into wedges.

Sprinkle half of the ¾ oz Parmesan over roasted potatoes. Roast on lower oven rack until potatoes are golden brown and crisp underneath, 10-12 minutes.

Pat 12 oz boneless, skinless chicken breasts dry and pound to ½-inch thickness, if desired. Rub each breast with chopped oregano and season all over with salt and pepper. Heat 1 tablespoon olive oil in a medium skillet over medium-high. Add chicken and cook until browned and cooked through, 3-4 minutes per side. Transfer chicken to a plate.

Melt 2 tablespoons butter in same skillet over medium-high heat. Add sliced garlic and onions; season with salt and pepper. Cook, stirring occasionally, until onions are softened and golden, 3-4 minutes. Add broth mixture, scraping up any browned bits from the bottom of the skillet. Bring to a boil. Meanwhile, pick and coarsely chop ¼ oz fresh parsley leaves; discard stems.

Add chicken, 5 oz peas, parsley, and remaining oregano to sauce. Simmer over medium-low until peas are warmed, 2-3 minutes. Transfer chicken to plates. Add potatoes to skillet, stirring to coat in sauce. Serve chicken with potatoes and peas, spooning lemon-herb sauce over top. Sprinkle with remaining Parmesan. Pass any lemon wedges for squeezing over. Enjoy!