1. Preheat your oven to 200°C.
2. In a bowl, mix olive oil, minced garlic, and rosemary, then toss the chicken breast in the mixture.
3. Peel and dice the sweet potato and carrot into even chunks, and arrange them on a baking tray; place the chicken on top.
4. Roast for 25-30 minutes until the chicken is thoroughly cooked and the vegetables are tender.
5. Add the peas in the final 5 minutes to warm through, then serve immediately for a nutritious lunch.

Summary:
A satisfying, adult-friendly lunch combining herb-infused chicken with roasted sweet potato, carrot, and fresh peas.

Storing Options:
Keep any leftovers in an airtight container in the refrigerator for up to 2 days and reheat gently to maintain texture.

Possible Side Effects/Allergies:
Contains chicken; verify seasonings for any additional allergens.