Preheat the oven to 350 degrees. Gather together all of your ingredients and measure them.
Pour one cup of apple juice or apple cider into a small saucepan, heat until boiling then turn the heat down just a bit and simmer until the juice has been reduced by half. Let cool to room temp.
Pour the lemon juice into the milk and let sit for a couple minutes.
Pour all dry ingredients into a large mixing bowl or the bowl of a stand mixer. Mix until combined.
Add the milk and lemon mixture, the apple cider reduction, eggs, vanilla, and butter to the bowl with the dry ingredients. Mix together until everything is fully combined.
Spoon your batter into a piping bag or into a 1 gallon zip top bag and snip one bottom corner.
Prepare a donut pan by spraying with non-stick baking spray. Pipe the batter into the prepared donut pan.
Bake the donuts in a preheated oven at 350° for 15 to 20 minutes until fully baked. The cake should be springy to the touch. Turn the donuts out onto a cooling rack and let cool completely before decorating.