Place steak in the freezer for about 45 minutes. Once firm, slice into thin 1/8″ strips, the thinner the better, really. Coat in 1 tablespoon oil and set aside.
Cook fries per package instructions; keep warm.
CHEESE SAUCE
Melt butter in a medium saucepan.
Once the bubbling has subsided add flour and cook for 1-2 minutes until light brown.
Slowly add warm milk to the butter-flour mixture, stirring constantly. Cook 4-5 minutes until thickened.
Remove from heat and slowly mix in cubed cheese until melted.
Cover and cook on the lowest heat possible until it fully incorporates, stirring periodically. Keep warm.
MEAT, PEPPER, & ONION MIXTURE
Preheat a large saute pan over high heat.
Add meat to pan and cook, over high heat, until no longer red.
Remove from pan and set aside.
Return pan to heat, add additional oil (if necessary) and add the peppers and onions.
Cook, stirring often until peppers are softened and onions are browned.
Return meat to the pan, stirring into the pepper and onion mixture.
Cook until the meat, peppers, & onions are caramelized. Remove from heat.
ASSEMBLING THE FRIES
Place cooked fries on a platter or sheet pan (see note).
Scoop meat mixture over fries.
Pour half of the cheese sauce over fries and meat.
Serve remaining sauce on the side.
Notes
Since the meat and vegetables are cooked over high heat, I recommend having everything prepped and ready to go before you heat your saute pan. This will reduce the chances of accidentally overcooking any of the components.
I prefer ribeye steak, but you could substitute sirloin, top round, or even ground beef for the ribeye.
I cook the fries on a parchment paper-lined sheet pan and serve the whole thing directly from the pan.