Garlic and Mustard Crumbed Chicken

A neighbor gave me this recipe a long time ago. I've always liked it - the crumb coating reminds me of stuffing. Leftovers are good sliced and put on top of a green salad.1 cup gluten free breadcrumbs, plus more as needed1/4 cup olive oil1/4 cup lemon juice1/4 cup dijon mustard1 minced clove garlic2 tbsp. chopped fresh parsley or 2 tsp. dried parsley2 - 4 skinless, boneless chicken breast