- Preheat the oven to 350°F.
- To make the cake: Combine the butter, sugar, lemon zest, and orange zest in a mixing bowl. Beat at medium speed until light in color, about 5 minutes.
- Scrape the bottom and sides of the bowl and add the sour cream. Mix to combine. Add the eggs one at a time with the mixer running. Add the Measure for Measure flour, baking powder, baking soda, and salt, mixing until smooth.
- Butter the inside of a 10- to 12-cup Bundt pan. Scrape the batter into the pan and bake for 40 to 45 minutes, until the top of the cake is golden brown and a toothpick inserted in the center comes out clean. Remove the cake from the oven and let it cool in the pan for 10 minutes, then invert it onto a cooling rack. Let the cake cool completely before glazing.
- To make the glaze: Combine the confectioners' sugar, lemon zest, orange zest, and 2 tablespoons lemon juice, mixing until the glaze is thick but pourable. Add more lemon juice needed. Drizzle glaze over the top of the cooled cake.
- Store any leftovers at room temperature, well wrapped, for several days. Freeze for longer storage.