In a large bowl, toss the potato chunks with 2 tablespoons of olive oil, half the garlic, rosemary, and season with salt and pepper.
Spread the potatoes on a baking sheet in a single layer.
In the same bowl, add the chicken breasts with the remaining olive oil, garlic, and a bit more rosemary. Season with salt and pepper.
Place the chicken among the potatoes on the baking sheet.
Bake in the preheated oven for about 40 minutes, or until the chicken is cooked through and the potatoes are tender.
Let the chicken rest for 5 minutes before serving.
Notes
Pat the chicken dry before seasoning for the best results.
• Cut potatoes into similar-sized pieces for even cooking.
• Mix the potatoes and chicken well with oil and seasoning to coat thoroughly.
• Let the chicken rest for a few minutes after baking for juicier meat.
• Use a meat thermometer to ensure chicken is cooked safely to 165°F (74°C).