Prepare three bowls: put eggs (and whisk them with a fork) in a bowl, flour in a bowl, and breadcrumbs and parmesan in the third bowl.
Heat olive oil and half the butter in a skillet on medium heat.
Prepare chicken by cutting them in half lengthwise (butterfly them then cut them so there's 4 pieces of chicken in total). Sprinkle them with garlic powder and salt and pepper, to taste.
Dunk the chicken pieces one by one first in the flour, then the egg, and then the parmesan/breadcrumbs. Once all the pieces of chicken have been breaded, add them to the pan. Cook them for about five to seven minutes per side.
While the chicken is cooking, chop the herbs.
Once you've cooked the chicken, remove them to a plate and set aside.
Add the Dijon mustard, remaining butter, lemon juice, water, and herbs to the skillet. Stir to ensure it's a consistent mixture.
Add the chicken back into the pan and cook for a few more minutes until the sauce has slightly thickened and the chicken is cooked through. Take care not to overcook the chicken.
Serve immediately with sauce drizzled on top of the chicken.