Preheat the oven to 350 degrees F. Spray a donut pan with nonstick spray and set aside.
Beat the butter and both sugars together until creamy. Add the eggs one at a time and beat until well combined, scraping down the sides of the bowl each time.
Whisk the flour and baking powder together and gradually add to the batter.
Add the preserves, vanilla and milk and beat until well mixed and smooth.
Using a large piping bag, pipe the batter into each space in the donut pan level with the surface.
Bake in the oven for 12-13 minutes and let cool for 5 minutes before transferring to a wire rack to cool. Repeat until all of the batter has been used.
Once the donuts are cool, make the glaze by mixing the powdered sugar, milk, vanilla and red food coloring in a microwave safe bowl. Prepare your sprinkles on plate ready to dip your glazed donuts into.
Mix well until smooth and then heat in the microwave for 10 seconds at a tie until the glaze is pourable but not too runny. Dip the donuts into the sprinkles and let set while you make the buttercream.
Beat the butter and half of the powdered sugar until smooth. Add the remaining powdered sugar and beat slowly at first then on high speed for 3-4 minutes.
Add the vanilla, milk, preserves and coloring and mix well.
Pipe a large swirl of the buttercream in the middle of the donut and decorate with more sprinkles and mini marshmallows.
Serve at once or keep covered at room temperature. These donuts are best eaten on the day they are made.