Preheat the oven to 400 degrees and prep your doughnut tray.

In a mixing bowl, thoroughly combine the wet ingredients - milk, vinegar, peanut butter, maple syrup, and vanilla extract. 

To the bowl of wet ingredients, sift in the dry ingredients. Your dough is ready! 

Add the dough to a piping bag or ziplock bag and cut off the corner so you can pipe out the doughnut mixture. 

Pipe the mixture using your bag into the doughnut moulds. I used a regular sized doughnut tray and this amount was perfect for 6 doughnuts. This dough does not rise much so don't be afraid to nearly fill the compartments!

Place in the oven and bake until cooked through - should only take about 7-10 minutes so watch carefully!

While the doughnuts are cooking, make your icing. I made my icing using freshly pureed concord grapes but this recipe would be just as delicious using the same amount of jam. To puree the grapes, add the grapes to a food process to blend. Strain the mixture through a mesh strainer to extract just the liquid - this is what you will use to make your icing. 

In a bowl that will be large enough to dip your doughnuts into, combine icing sugar, grape puree (or jam) and vanilla extract. You want your mixture to be slightly runny but not watery - add more liquid if necessary. Set aside until you are ready to ice your doughnuts.

Allow your doughnuts to cool completely before icing. When you remove your doughnuts from the tray the bottom is perfectly smooth - I flipped the doughnuts upside down and made this the top for a super smooth finish. Give the icing a fresh stir and dip your doughnut into the bowl of icing just to cover the top. Prepare to be amazed - this is so satisfying! Enjoy!