Remove dough from refrigerator and let thaw until needed, ~20 minutes.
On cutting board slice red onions into thin strips. In large skillet, saute onions in 2 tsps EVOO over medium flame, gently seasoning with salt & pepper as they soften. Stir regularly until lightly caramelized (~20 minutes) then remove from heat.
While onions cook, evenly space frozen chicken on microwave safe plate. Microwave for 1 minute - 90 seconds until warm but not fully heated, then remove. With a sharp knife slice chicken into strips, then set aside.
When ready, amply flour counter before rolling out dough into 12 inch diameter. Transfer dough to lightly greased pizza sheet, then drizzle the center with 1 tsp EVOO, spreading well with a basting brush. Next, evenly build a thin layer of red onions, then a circle of sliced chicken. Top with cheddar cheese, then fold over the hanging edges to create a crust. Brush last remaining tsp EVOO over crust.
Bake pizza at 425F for 15 - 20mins until crust has cooked and cheese has melted. Immediately plate and serve, garnishing with fresh parsley if desired.