Preheat the oven to 325°F. Grease a (10-inch, 12 cups) bundt or tube pan with solid vegetable shortening and sprinkle with sugar (or you can use flour). Alternately, you can use Wilton Cake Release. Position the oven rack in the center of the oven.
Sift the flour, baking powder, and salt into a bowl. Whisk to combine.
In the bowl of an electric stand mixer, using the paddle attachment, beat the butter at medium speed, for about 3 minutes, until very creamy.
Add the sugar and beat for about 3 more minutes.
Beat in the eggs one at a time, beating for 30 seconds after each addition. Stop the mixer and scrape down the sides and bottom of the bowl with a rubber spatula.
At low speed, beat in the flour mixture in 3 additions, alternating it with the whipping cream and limoncello liqueur. Begin and end with the flour mixture.
Scrape down the sides of the bowl thoroughly after each addition.
Stop the mixer and scrape the batter. Mix again then evenly spoon the batter into the prepared pan. Bake for 75 to 85 minutes, or until a pick comes out clean or with dry crumbs. (You know your oven, bake accordingly, 80 minutes worked for me.
Cool the cake in the pan on a rack for 20 minutes. Carefully, loosen from the pan and invert on a cake pan.
FOR THE BUTTER SAUCE
Combine the sugar, butter, and water in a small saucepan and place over medium heat. Stir until the sugar melts, about 5 minutes.
Remove the pan from the heat and whisk in the Limoncello. Poke holes in the warm cake and spoon the hot syrup over the surface of the cake and let it soak into the cake.
FOR THE GLAZE
In a medium bowl, whisk the limoncello and powdered sugar. (Add more limoncello or powdered sugar until you reach the consistency you desire.)
Let the cake cool completely and drizzle the glaze over the top.
Store cake in an airtight cake taker in the refrigerator or counter.