Preheat oven to 375 degrees. Lightly spray a donut pan with nonstick cooking spray.
In a medium bowl, combine the dry ingredients {flour through baking soda}. Stir gently to combine.
In a large bowl, whisk together egg and buttermilk until just combined. Slowly stir in dry ingredients. Mix in melted butter and vanilla. Stir in red food coloring until you get the shade of red you want. 3/4 Tbsp was perfect for me but you can play around with it.
Fill donut wells about 2/3 full. Bake in preheated oven for 8 minutes. Let cool in the pan for 2-3 minutes before transferring to wire cooling racks to cool completely.
Beat cream cheese until smooth. Stir in sugar and beat until smooth. Slowly add in heavy cream by the tablespoon until you reach the consistency you want. Frost cooled donuts.