Catalan coca (Spanish pizza)

Ahead of time

1. To make the base, put the flours, yeast, salt and sugar in a large bowl and mix together. Make a slight well in the middle and add the oil and water and carefully mix together into a dough (you can also just simply add all together in a bowl and mix as in video but you need to take care that everything mixes well). It should be slightly sticky as it comes together in a ball.
2. Tip the dough out onto a floured surface and knead for about 5 minutes, stretching the dough away from you with the back of your hand, folding the stretched part over on top of the rest of the dough, turning 90 degrees then repeating. Add a little more flour as you go, if needed, but only a little at most. After around 5 minutes it should stop feeling sticky. Clean out the mixing bowl, lightly oil it then form the dough into a ball and put it in the bowl. Cover with cling film/plastic wrap and leave it to rest somewhere warm room temperature for about an hour, possibly more, until it doubles in size.
3. While the dough is rising, prepare the topping. Thinly slice the onions and peppers. Warm the oil in a medium skillet/frying pan over medium heat and cook the onions, stirring regularly, until just starting to soften. If they start to brown at all, reduce the heat. Add the peppers then continue to cook until the onions and peppers are both very soft and onions starting to caramelize (they should be very soft and going slightly darker but not charring in any way). Set aside. 

As ready to cook

1. When ready to make the coca, preheat oven to 425F/220C. Put baking sheets in the oven to allow them to pre-heat.
2. Knock back the dough (prod with your fingers after turning it out of the bowl) and divide into 2 (alternatively, you can make one large pizza or more smaller). Keep the piece(s) you are not working with to one side, covered, while you work on the one pizza.
3. Stretch out the pizza dough into a circle or rectangle, as you prefer, and as suits your baking sheet/tray. Roll it about as thin as you can and transfer to a piece of parchment paper. Repeat with the remaining dough.
4. Top the cocas with the onion-pepper mixture then sprinkle over the paprika. Bake for approx 10-12 minutes until the base is lightly brown. Trim off any burnt pieces of onion, if you have any, and serve.