For the donuts: Preheat the oven to 375 degrees F. Coat a 12-cavity donut pan with cooking spray and set aside.
Whisk together the flour, granulated sugar, baking powder, salt, baking soda and zest in a large bowl. Whisk together the egg, buttermilk, oil, vanilla, almond extract and 1/4 cup water in a medium bowl. Add the wet mixture to the dry mixture and stir until just combined.
Fill a piping bag or resealable plastic bag with a corner snipped off with the batter and pipe the batter into the donut pan, filling each cavity halfway. (If you have any remaining batter, you can bake it in a second batch.)
Bake until a toothpick inserted in a donut comes out clean, about 12 minutes. Cool in the pan for 5 minutes, then remove to a rack and cool completely. (A mini spatula helps remove them from the pan!)
For the vanilla glaze: Mix together the powdered sugar, corn syrup, vanilla, salt and 3 tablespoons milk in a medium bowl. Add additional milk little by little until the mixture is pourable, up to the remaining tablespoon. (Be careful not to add too much milk, because the glaze should be thick and opaque, but if the glaze is too thick it will have a hard time sticking to the donuts. You can always make adjustments by adding more powdered sugar to make it thicker or more milk to thin it out.)
Place a baking sheet or piece of parchment paper underneath the rack with the donuts and dip each donut halfway into the vanilla glaze, scraping off any excess glaze from the bottom and returning to the rack. Let the vanilla glaze dry 20 to 30 minutes if you're impatient like me, but more like an hour or so if you want it to really be nice and solid.
For the chocolate glaze: Stir together the powdered sugar, cocoa powder, corn syrup, salt and 3 tablespoons milk in a medium bowl, using the same method as you used for the vanilla glaze. Carefully dip the unglazed half of the donuts into the chocolate glaze. (For the chocolate side, I find it's helpful to use a spatula to help the glaze nudge right up against the vanilla.) Scrape any excess glaze off the bottom, then place back on the rack, and let dry 1 hour. Enjoy!
These are best the day of, but they keep for an additional couple of days at room temperature in an airtight container.