Help needed making Stromboli

Inspired by this thread I have decided to finally learn how to make stromboli & not create a disaster.

My stromboli always basically explodes in the oven & falls apart.

I am looking for detailed information on how to be a Stromboli Success.

And by stromboli I mean LifeOnWry’s description of stromboli:

HELP!

Unfortunately Roberto Rossellini has passed away.

http://www.fabulousfoods.com/recipes/main/sandwiches/stromboli.html

Slicing the top in Step 3 is very important. It’s like docking a pie crust. It lets steam out so the baked item doesn’t expand too far and burst open.

I ran across a bakery that makes a similar rolled loaf, but flattens it out a little. They cut an inch or so apart almost down to the bottom layer and then fan the slices left and right so it looks a bit like a braid. The fillings to choose from, if I recall, were spinach with feta, pepperoni with cheese, and a fairly plain tomato sauce with garlic.

Thanks! I think that’s what I’m doing wrong.
I’ll be making this on Saturday night. Yay!