Instructions

  1. Preheat the oven to 350°F.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. Store any leftovers at room temperature, well wrapped, for several days. Freeze for longer storage.