Begin by seasoning the chicken breasts with garlic powder, salt, and pepper on both sides.
Heat the olive oil in a large skillet over medium-high heat. Once the oil is hot, add the seasoned chicken breasts and cook for 6-7 minutes on each side or until golden brown and cooked through. Remove the chicken from the skillet and set aside.
In the same skillet, add the chicken broth, scraping any browned bits from the bottom of the pan. Bring it to a simmer.
Reduce the heat to low and stir in the heavy cream, lemon zest, lemon juice, chopped dill, and Dijon mustard. Mix well and let it simmer for about 3-4 minutes.
If a thicker sauce is desired, mix the cornstarch with a tablespoon of cold water until smooth, then stir it into the sauce and cook for another minute until it thickens.
Return the chicken to the skillet, spoon some sauce over the top, and let it cook for an additional 2-3 minutes to ensure everything is warmed through.
Serve the chicken hot, drizzled with the creamy lemon dill sauce.
Notes
Plate the chicken on a bed of steamed rice or buttery mashed potatoes, garnished with fresh dill and lemon slices.