Trim fat from chicken filets and coat a large rectangle foil pan with butter.
In a medium bowl, combine cheese shreds, panko crumbs, garlic powder, salt, black pepper, and oregano.
In a small bowl, whisk the egg with 1 tsp. (5 mL) minced garlic until frothy.
Sprinkle the tops of each chicken filet with a little flour, making sure it is evenly coated. Next, dip each filet top in the egg mixture. Then, dip the tops in the panko cheese blend and place, tops up, in the center of the foil pan.
In a food processor or blender; puree olive oil, sundried tomatoes, garlic, basil, salt, and lemon juice until almost smooth, about 2 minutes. It is okay to have a few nice pieces of tomato in the mix when done blending.
In a medium bowl, toss frozen Brussel sprouts together with the sundried tomato and lemon puree. Pour equal amounts on either side on the chicken filets in the foil pan.