Panko Crusted Beef Sandwich-Thit Bo Chien Xu Kep Banh Mi

Serves 4
8 thick slices of white firm bread, toasted
3/4 to 1 lb filet mignon or any tender cut beef , cut into 1/2 in thick, flatten with a meat mallet
3/4 cup panko
1 egg, light beaten
1/4 cup flour for dredging
salt and ground black pepper to taste
1/2 cup of thinly shredded cabbage, white or red, or mix coleslaw
vegetable oil for frying
4 Tbs mayonnaise
3Tbs mustard butter, mix 2 Tbs unsalted butter (at room temperature) with 1 Tbs Dijon mustard
4 Tbs Tonkatsu sauce (recipe in Tonkatsu post0

1. Prepare and cook panko crusted beef steaks like Tonkatsu: season both sides of beef steaks with salt and pepper;dredge each steak in flour/shake off any excess; dip in the egg; then coat with panko. Do remember keep one hand wet (for egg only) and one hand dry( flour and panko) for less messy.  Heat oil in a large skillet (need about 1/2 in deep of oil) over medium high heat until oil is shimmer.  Add beef, frying until golden brown, turn once, cook 3 to 5 minutes to your liking.  Drain on cooling rack or paper towels. 
2. Toast bread, spread mustard butter on one side of 4 slices of bread and mayonnaise over the other slices. Top with beef, 1 Tbs Tonkatsu sauce (recipe in Tonkatsu post) and 1/4 of cabbage. Top with the remaining bread slices.  Cut into 2 and serve.

*If you do not like mustard just use butter by itself.