Preheat the oven to 350 degrees F. Grease and flour the donut pan. Even though the donut pan is non-stick, the banana makes the dough sticky, so it works better to grease and flour the pan.
Mix the buttery spread, mashed banana, and sugar in a large bowl. Add the vanilla, vinegar, and non-dairy milk, stir.
Add the dry ingredients and nuts to the wet mixture and mix together. The dough will be soft, and not too wet. Let the dough rise for a minute.
Spoon the dough into the donut pan. Each well will be full almost to the top. Smooth out the dough with the back of a spoon. Make sure that the center of each part (where the hole will be) is free of dough.
Bake for 10-12 minutes. Let cool in the pan for a few minutes, then remove.
Melt the chocolate chips in the microwave for 45 seconds, stir. Microwave for 10 second intervals, stirring in between, until the chocolate is melted and smooth.
Spread the chocolate on the cooled donuts and top with the walnuts and a sprinkle of sea salt if desired.
Notes
Store leftover donuts in an airtight container. They should stay fresh for about 3 days.If you want to freeze these, wrap each donut in waxed paper, and place in a freezer bag. They should stay fresh for about 3 months.You can leave the nuts out of this recipe if you like.