The Stromboli is like a big rolled-up pizza. With all the lovely stuff you would use on a regular pizza, except it's enclosed within the dough instead of being put on top of it!
Next prepare the dough. You will need:
2 ½ cups all-purpose flour
1 ½ tsp. salt
5 tbsp. oil
1 ½ tsp. sugar
1 ½ tsp. instant yeast (use 2 tsp. for colder climates)
2 pinches of baking powder
warm milk mixed with a bit of water for kneading
Mix all the dry ingredients and the oil, then slowly start adding the warm milk a little at a time. Get it to a soft dough, the softer the better, knead it very well for at least 8 minutes or more if possible.
Dab a touch of oil all over the dough, then cover it and place it somewhere warm. Leave it to rise to double its size, takes about 30 minutes to an hour depending on the weather.
Once ready, punch down the dough and then roll it out into a rectangle of about quarter inch thickness.
Spread the pizza sauce all over the rectangle, leaving about an inch all around the sides.
Add the filling, drizzle a bit of ketchup and scatter some cheese over it. Try not to over fill because this rectangle will be rolled up like a swiss roll with the filling inside, and if it is too full it might trouble during rolling.
Starting from the side closest to you (one of the longer sides), gently roll the rectangle like a swiss roll or tube.
Bring the two ends of the 'tube' together so it looks like a tier or circle. Pinch them together gently. So now you have a round roll. Gently lift and place this on a greased baking tray.
Using a SHARP knife, make slits in the tube, all around. Don't cut the dough all the way through otherwise the stromboli will fall apart. Just cut through the layers without touching the bottom layer. Then gently 'fan' out or spread the circle so it stretches out slightly. This will ensure that the heat gets a chance to go all the way into the Stromboli making sure it cooks through to the inside.
Pre-heat the oven at 180 C.
Brush an egg beaten with 1 tbsp. milk all over the stromboli.
Bake in the pre-heated over for about 25-30 minutes, or until it's golden and cooked through.
Let it rest for some minutes before slicing to give the cheese time to set and cool slightly inside.
Serve and enjoy! :)