To make the pizza dough, 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, yogurt and water and carefully mix together into a dough. It will be slightly wet and sticky. 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. After around 5min 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 for about an hour, possibly more, until it doubles in size.
While the pizza dough is rising, thinly slice the onions. Warm the butter and oil in a large skillet/frying pan and add the onions. Cook, stirring now and then, over a medium heat, until they are soft and gently caramel colored - it will take a good 25-30 minutes. Reduce the heat if they get too brown or start to burn. Set aside.
Prepare a piece of parchment big enough to hold all the pecans. Toast the pecans either under a broiler or in a dry skillet until just starting to smell but not burning. Toss with the maple syrup, away from the heat, and move around quickly so they are all covered. Tip onto the parchment and separate out the nuts. Leave to cool then break them up into small-ish pieces.
As ready to cook
When ready to make the pizzas, preheat oven to 450F/230C. Put baking sheets in the oven to allow them to pre-heat.
Knock back the pizza dough (prod with your fingers after turning it out of the bowl) and divide into 4. Keep the pieces you are not working with to one side, covered, while you work on the one pizza.
Roll 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 rest of the dough.
Top each piece of dough with ¼ of the onions, spreading out evenly. Crumble over the gorgonzola. Bake for around 6-8 minutes until just starting to brown.
Add the pecans on top then bake another 3-4 minutes. Once the crust is lightly brown and crisp, serve, topped with chopped green onions. Cut into slices, if you prefer, to be more finger food.
Notes
Not prep time doesn't include rising time, but some of it will be spend preparing/cooking topping.