Preheat the oven to 180C (160C fan forced).
Grease a 20cm pie or quiche dish.
Dust the greased dish with flour and set aside.
Mix the flour, mustard powder, and cayenne pepper together in a small bowl. Set aside.
Heat a small fry pan over a medium-low heat.
Fry the onion in 2 Tablespoons of the olive oil for five minutes, or until slightly browned.
Add the bacon to the fry pan, and cook for a further five minutes, or until the bacon begins to brown.
Place the cooked onion and bacon in a large bowl.
Add the zucchini, grated cheese, olive oil and eggs.
Stir together thoroughly.
Add the flour mixture and mix until the flour is just incorporated.
Tip the batter into the floured quiche dish.
Bake for 30 - 40 minutes, or until the quiche is well risen and lightly browned.
Allow to rest at least 5 minutes before serving.