To make the dough, add the water in a jug, mix in the yeast, olive oil and sugar and a tablespoon of flour.
Set aside for 10-15 minutes until the mixture becomes frothy.
In a large bowl, combine flour and salt, then, pour in the yeast mixture, garlic powder and oregano.
Knead into a dough for 5 minutes until it's elastic and no longer sticks to your hand - use more flour if necessary.
Shape the dough into a ball.
Slightly oil the bowl and the dough, cover with clingfilm and a clean tea towel, then leave to prove for 1-2 hours until it doubles its size.
Preheat the oven to 180 degrees Celsius (350 Fahrenheit).
Transfer the dough to a lightly-floured work surface, knead it around for a bit to push the air out, then divide it into two equal balls and roll one ball to the size of your pizza pan.
You can either make the second pizza at the same time, or wrap it in clingfilm and refrigerate the second dough ball to use it later on.
Cut the peppers into strips.
Spread the tomato sauce over, add the mozzarella cubes, mushrooms cut into slices, peppers and olives.
Sprinkle some oregano and cheddar cheese on top, then one pizza is ready to go in the oven.
Bake for 20 minutes until the crust is golden and the cheese is melted.
Serve hot!