Creating the Italian Grinder Sandwich is a delightfully simple process when you follow these steps:

1. Prepare the Bread: Slice the hoagie roll in half lengthwise, ensuring not to cut all the way through.
2. Mix the Dressing: In a small bowl, whisk together olive oil, red wine vinegar, Italian seasoning, salt, and pepper.
3. Layer the Ingredients: Begin by placing the sliced salami on the bottom half of the hoagie roll.
4. Add Mortadella and Cheese: Layer the sliced mortadella followed by slices of provolone cheese.
5. Add Fresh Vegetables: Top with shredded lettuce, sliced tomato, sliced red onion, and pepperoncini for that extra zing.
6. Drizzle Dressing: Lightly drizzle the prepared dressing over the layers for added moisture and flavor.
7. Close the Sandwich: Gently close the sandwich, pressing down slightly to hold the fillings in place.
8. Toast (optional): If desired, toast the sandwich on a pan over medium heat for about 5-10 minutes until the bread is golden and the cheese is melted.
9. Cut and Serve: Once toasted, slice the sandwich in half and prepare it for serving.

By following these straightforward steps, you’ll have an authentic Italian Grinder Sandwich ready in no time!