Mix all ingredients for the jalapeno cilantro crème together in small bowl. Stir until combined. Chill until time to serve to let the flavors blend.
Butterfly chicken breasts & open. Set aside.
Mix egg, 1 T water, & 1 T sour cream till well blended and smooth.
In shallow dish mix breadcrumbs, cornmeal, and spices together.
Heat non stick skillet over med heat and add oil to just barely cover the bottom of the pan. More oil may be needed as the chicken cooks and the breading crisps.
Dip butterflied chicken breasts into the egg mixture, then into the cornmeal spice mixture. Turn to coat. Firmly press on chicken breast with the heel of your hand while in the breading mix to flatten as much as possible and to adhere coating. Repeat on second side. The chicken should be as even in thickness as possible.
Place chicken breasts into heated pan , fry until golden on first side- approx 4 minutes. Turn over and pan fry the other side until golden, approx 3 minutes more depending on thickness of chicken. Remove when done.
Serve with jalapeno cilantro crème on top or alongside.