Slice the chicken breasts to get 4 pieces. Pound the pieces to even thickness. Make sure each piece is 4 ounces.
Add chicken, potatoes, bell pepper, onion, carrot, and garlic to a large bowl. Drizzle with olive oil and add all seasonings. Season with salt and pepper (I use about 1 teaspoon salt & 1/4 teaspoon pepper). Toss to evenly coat.
Lay out 4 large foil sheets. Evenly divide the mixture between the sheets, placing 1 piece of chicken in each. Top each packet with 1 tablespoon butter. Seal the foil tightly.
Cook: until the chicken is completely cooked through (registers 165°F).Grill: 15–25 minutes (mine finishes around 20 minutes).Oven: 30–45 minutes, or until chicken reaches 165°F internal temp (mine finishes around 35 minutes).
Carefully open foil packets to release steam. Top with a drizzle of olive oil, chopped parsley, lemon juice, and lots of freshly grated Parmesan. Add more salt and pepper, if needed.
Stovetop Cooking Option: Follow steps 2-3.In a large skillet, heat 2 tablespoons oil. Add chicken in a single layer and cook for 2–4 mins per side. Add 1 tablespoon butter after flipping. Cook until chicken is fully cooked through. Transfer to a plate and cover with foil.Add more oil if needed and another 1 tablespoon butter. Cook all veggies until crisp-tender, stirring occasionally.Plate chicken and veggies together. Top with Parmesan and fresh lemon juice.
Video
Notes
Note 1: Serving suggestions: an extra drizzle of good olive oil, fresh lemon juice, finely chopped flat-leaf parsley, and freshly grated Parmesan. (I grab a block of Parmesan and grate it with a microplane for the best texture!)Storage: Store leftovers in an airtight container (not foil) in the fridge for up to 3 days; foil can give the food a metallic flavor. To prep ahead, mix everything in a bowl, cover tightly, and transfer to foil just before cooking.