Arrange a rack in the middle of the oven and heat to 350 degrees F.
Cream together the remaining 16 ounces of butter and the sugar in the bowl of a stand mixer for 5 minutes on medium speed, using the paddle attachment. Stop once to scrape down the sides of the bowl with a spatula. With the mixer running at the lowest speed, add the eggs, 1 at a time, making sure each egg is fully incorporated before adding the next. Again, stopping once to scrape down the sides of the bowl. This will take approximately 3 minutes and the mixture may look curdled. Add the vanilla and salt and beat on medium speed for 30 seconds.
With the mixer on the lowest speed, add the flour in 3 installments, making sure each portion is fully incorporated before adding the next. After the final addition, scrape down the sides of the bowl and then beat for 30 seconds on medium speed until almost smooth.
Scoop the batter into the prepared pan(s), dividing evenly if using 2 pans. Bake for 1 hour or until the internal temperature reaches 210 degrees F on an instant-read thermometer. The crust will be golden brown and will spring back when pressed, but the crack around the center will appear moist.