This is one recipe whereI do use a convection oven preheated at a temperature of 390°F for the entire bake time of 20 - 25 minutes If you do not have a convection oven, set a standard conventional oven to 450°F and once you place the pate a choux in the oven turn it down to 400°F for the baking time of about 20 -30 minutes Due to the high heat necessary to bake these- I also prefer to always usea silicone baking mat to avoid singing the parchment paper, however it is not imperative. Just a preference of mine. Bread flour is the best option for making pate choux as it has the highest ability to absorb the liquid in the recipe which is a key to success in pate a choux making. If you do not have bread flour all purpose may be used, but you may need to add another tablespoon or 2