Preheat the oven to 325ºF. Generously grease and flour a 12-cup Bundt pan and set aside.
In the bowl of a stand mixer or in a large mixing bowl using a hand mixer, cream butter, and sugar together until light and fluffy.
Beat in the sour cream, then eggs, lemon extract, vanilla extract, lemon juice, and zest until smooth.
Add half of the flour mixture, baking powder, and salt, and mix until smooth.
Add remaining flour and mix until smooth and blended.
Pour batter into the prepared Bundt pan.
Bake in the center of the oven and bake for 85-90 minutes, until a toothpick inserted comes out clean. (I start checking the cake at 80 minutes).
Remove from oven and let cool for 10 minutes
Loosen the cake from the sides of the pan with a butterknife or icing spatula and turn it onto a wire rack to finish cooling.
When the cake is cool, whisk the icing ingredients together and drizzle over the cake.