In a large mixing bowl combine the flour, baking powder and salt. Pour in the water and oil and mix until well combined. Let dough rest 10 minutes.
Brown the sausage breaking up into tiny pieces until cooked through. Set aside.
Preheat oven to 450°F. Lightly oil a 16 inch pizza pan or baking sheet.
Roll out dough and place on your oiled pan. Bake dough in the preheated oven for 5 minutes.
Remove dough from oven and spread the tomato sauce evenly over top. Sprinkle on the mozzarella cheese, cooked sausage and the the sliced onions. Place back in the oven for 12 to 14 minutes or until crust is crispy and a light golden color.
Remove pizza from oven and sprinkle with the fresh basil and parmesan cheese. Cut into squares and serve.
