01 -
Preheat the oven to 325°F (163°C). Grease and flour a standard 12-cup Bundt pan to prevent sticking.
02 -
In a medium bowl, whisk together the flour, cornstarch, baking powder, and salt. Set aside.
03 -
Using an electric mixer with a paddle attachment, cream the butter and granulated sugar on medium speed until light and fluffy, about 3 minutes.
04 -
Mix in the instant lemon pudding mix powder (do not cook it). Combine thoroughly.
05 -
Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next.
06 -
Mix in the fresh lemon zest.
07 -
In a large measuring cup or bowl, combine the milk, canola oil, and vanilla extract.
08 -
Alternately add one-third of the dry mixture and one-third of the wet mixture into the batter, starting and ending with the wet ingredients. Mix thoroughly after each addition. After the last addition, mix on medium speed for 2 minutes to ensure a smooth batter.
09 -
Transfer the cake batter to the prepared Bundt pan, spreading it evenly.
10 -
Bake in the preheated oven for 50 to 60 minutes, or until a toothpick inserted in the center comes out clean.
11 -
Invert the cake onto a cooling rack and let it cool completely before frosting.
12 -
Frost the cooled cake with lemon buttercream icing and sprinkle additional lemon zest on top if desired.