I made these especially for the 4th, they were too good not to share.

What You'll Need: (makes 6 subs total)
-6 hoagie loaves
-1.15 LB sirloin tip steak thin (or any kind of thin steak for that matter)
-1 bell pepper, chopped
-half an onion, chopped (white or yellow)
-provolone slices
-mayo (squeeze bottle works best)
-1/2 a stick of butter
-black pepper
-garlic salt
-meat seasoning
-1 large frying skillet
-1 strainer

Step 1:
Start by tenderizing your meat, getting it as thin as possible, then cut it into thin strips a few inches long (meat scissors make it much easier).

Step 2:
Heat stove burners to med-high, add 1/4 of the 1/2 stick of butter to the skillet. When melted, toss in the steak and chopped bell peppers. Cook the meat until the red is almost cooked all the way through, but not fully.

Step 3:
When the meat is almost all brown, drain mixture in the strainer and return to skillet and burner. Add the rest of the butter, chopped onions, and spices to preference. Cook until onions have turned a nice golden brown and the meat has been cooked all the way through i.e. no more red. Turn off burner.

Step 4:
Take a hoagie loaf and cut it directly down the center on top like a hotdog bun and spread it open a bit like a purse. Add a thin layer of mayo on the bottom, then top with a generous amount of the steak/peppers/onion mixture. You want to get as much inside as possible, but not too much to overstuff. Split a slice of provolone in half and lay it directly across the top like a blanket. Spoon a bit more of the mixture on top, the cheese will melt from the heat of the steak. Repeat process with all 6 loaves accordingly

Step 5:
Top with any desired condiments (I used Dijon mustard because it's my fave) and enjoy.