Preheat oven to 375°F (191°C). Lightly grease three 6-piece donut pans with softened butter.
In a bowl, whisk together the all-purpose flour, cake flour, cinnamon, baking powder, ginger, salt, baking soda, and nutmeg until well combined. Set aside.
In the bowl of a stand mixer, using the paddle attachment, cream together the Redpath® Golden Yellow Sugar, melted butter, and oil on medium speed until pale in colour; 2 minutes.
Add in the egg yolks, egg, and vanilla extract. Mix on low speed until just combined. Increase speed to medium and cream until mixture is smooth.
Add in ⅓ of the dry ingredients to the bowl of the stand mixer and mix on low until just combined. Add in half of the buttermilk and blend on low speed until liquid is absorbed into the batter. Repeat the process with the remaining dry ingredients and buttermilk, ending with the dry ingredients; do not overmix.
Transfer batter into a piping bag fitted with a large plain/round piping tip. Pipe batter into the prepared pan until each depression is about ⅔ full.
Place the filled pan into the preheated oven. Bake for 8 to 10 minutes or until the surface of a donut springs back when gently pressed.
Allow donuts to cool in the pan for 5 minutes before turning them out onto a wire cooling rack to cool completely.