Peel 2 potatoes; cut into 1-inch pieces. Place in a medium saucepan with 1 teaspoon salt and enough water to cover by 1-inch. Cover, bring to a boil over high, then uncover and cook until easily pierced with a fork, about 10 minutes. Reserve 1/2 cup cooking water, then drain potatoes and return to saucepan. Cover to keep warm off heat until step 5.

Meanwhile, scrub and trim 3 oz carrots. Halve lengthwise and cut into 1/4-inch thick half-moons. Finely chop 1/2 teaspoon garlic. Finely chop 1/2 teaspoon rosemary leaves; discard stems. Pat 10 oz chicken breast dry; pound to an even 1-inch thickness, if desired. Season all over with kosher salt & ground pepper. In a liquid measuring cup, whisk to combine 1/2 cup water and 1 pkt turkey broth concentrate.

In a medium skillet, bring carrots and 3 tablespoons water to a boil over medium-high heat. Cover and cook until tender, about 2 minutes. Add 5 oz peas, 1 tablespoon butter, and all of the chopped garlic; cook until butter is melted and peas are warmed through, about 2 minutes. Season to taste with salt and pepper. Transfer to a plate and cover to keep warm; reserve skillet.

Melt 1 tablespoon butter in same skillet over medium-high. Add chicken; cook until browned and cooked through, 3-4 minutes per side. Transfer to a plate. To same skillet over medium heat, add chopped rosemary and 1 tablespoon flour. Cook, whisking until fragrant, about 30 seconds. Add broth mixture; cook, whisking until thickened and coats the back of a spoon, 3-4 minutes.

Return saucepan with potatoes to medium heat. Add 2 tablespoons butter, mash with a potato masher or fork until smooth, adding 1 tablespoon reserved cooking water at a time, as needed to reach desired consistency. Season to taste with salt and pepper. Serve chicken alongside mashed potatoes, peas, and carrots. Spoon herb gravy over top. Enjoy!