Prep: Preheat oven to 425F degrees. Line a large baking sheet with parchment paper.
Make Dough: Combine 1 cup flour, undissolved yeast, sugar, and salt in a large bowl. Add water and oil and mix together until well blended (you can do this by hand or with your mixer). Gradually add flour, mixing in 1/2 cup at a time, until dough forms a ball. Add additional flour, if needed to handle but dough should be slightly sticky.
Knead Dough: Spoon dough out of bowl onto floured surface and knead until dough is smooth and elastic; about 4 minutes.
Make a rectangle: Roll Stromboli dough out into a large rectangle, about 10 by 14 inches on the parchment paper.
Make sauce: Stir parsley, basil, oregano and crushed red pepper flakes to taste (do not use red pepper if you are using Hot Italian Sausage) into 1/2 cup marinara sauce.
Add toppings: Lightly spread sauce over the dough, leaving a 2 inch plain dough border along the edges. Top sauce with half the grated cheeses, followed by meats, then vegetables followed by remaining cheese.
Roll Stromboli: Brush the plain border of dough with the egg wash. Roll up the Stromboli lengthwise like a jelly roll and pinch edges to seal. Brush the entire Stromboli with egg wash and gently cut slats in the top of the dough every 1-2 inches. Sprinkle with freshly grated Parmesan and lightly sprinkle with garlic salt.
Bake: Bake at 425 degrees F until golden, 15-25 minutes depending on ingredients (see notes)*** covering with foil at the end of baking if necessary to prevent excess cheese browning.
Serve: Let cool 5 minutes before slicing. Serve with extra marinara sauce if desired.