In a small skillet, saute onion and garlic in 1/4 cup broth until onions are translucent. Then, remove from pan and set aside.
Season chicken breasts with salt and pepper.
Add 1/4 cup broth, 1 Tbsp lemon juice and chicken. Sear the chicken on both sides, then set it aside.
Add the onion and garlic back to the pan with remaining broth and lemon juice. Add arrowroot powder and fresh dill and whisk to combine.
Add the chicken back to the pan and simmer on low heat until chicken is cooked through.
Plate chicken and spoon remaining sauce over chicken. Garnish with fresh dill.