Deseed and slice peppers into strips.
Arrange strips on baking sheet, drizzle with olive oil and place in preheated oven at 425.
Cook peppers until the skin begins to blister, then remove from oven and set aside.
Season steaks with salt and pepper.
Heat skillet and when very hot add cooking oil and carefully place steaks in skillet.
Sear both sides of each steak until each steak has a dark crust on both sides - approx. 5 mins each side
Once steaks are seared remove from skillet and allow to rest for 10 mins.
Divide spinach, peppers, tomatoes, cucumber, caper berries and onions across four salad plates or bowls by layering each ingredient.
Slice steaks into 1/2 inch slices.
Add a layer of steak to each plate and sprinkle with feta cheese.
Shake balsamic vinaigrette vigorously once more and drizzle over each salad.
Serve immediately.