A calzone is basically a turnover or folded pizza. It contains the same ingredients as a normal pizza, but because it is folded-over, this pizza-version is neater and easier to pack and carry with you on a picnic or for your lunch at school/work.
First, sieve the flour and add the salt, sugar, baking powder, yeast and oil. Heat the water/milk as much as you can tolerate for kneading. The hotter the liquid, the softer the bun. Add the water gradually into the flour while kneading until you have a soft but firm dough. Knead the dough, pounding at it as much as you can to give the buns a delicately soft texture. The more you knead the better the results.
Put the dough into a lightly-oiled spacious bowl and turn it over in the bowl once so that the little oil covers the dough all over. Cover the bowl with a damp warm towel and let the dough rise for about 30-45 mins.
Once risen, divide into 4 balls. Roll out each ball into a circle of about 1/4" thickness. Spread some pizza sauce all over the circle, leaving a margin near the circumference. Next, scatter the toppings of your choice on one half of the circle. HERE's the link for the chicken I used. Make sure you do not over-load the calzone. Sprinkle the grated cheese over everything and drizzle some ketchup/tomato sauce over it.
Dip your fingers in some warm water then run them around the circumference of the circle of dough. Then fold the circle in half, using the empty half to cover the half that has the filling. Press down around the edge using a fork that's been dipped lightly in flour. This helps seal the edge and leaves a pretty design too.
Repeat for the remaining dough balls ...
Place the calzones on a greased tray and let them rise again for about 20-30 mins. Then lightly brush the tops with egg yolk beaten with 1 tbsp. milk to give them a nice golden color. Bake in a pre-heated oven (around 180 degrees) until they're golden and cooked. Should take about 15-20 mins depending on your oven.
You can apply a bit of butter when they are straight out of the oven (to give them an amazing aroma and to help soften them further). Make sure you cover them in a soft cloth for at least 15 mins before serving. This makes them extra soft.
Serve with fries, a cold drink or salad, or even on their own.