I recommend using a food processor to make a lot of my batters. However, adding flours into the mixture can be time consuming and messy if you have to take the lid off every time you want to add something. In addition to this, the opening of the top if often a lot smaller than the width of a standard cup measurer and it is difficult to get the flours in evenly without losing a lot of it and making a mess. A quick trick to make this easer is to create a funnel with some parchment (baking) paper. Place this funnel into the feeding tube and this will allow the flours to slide in slowly and evenly.