Bring butter, cream cheese & eggs to room temperature.
Lightly butter a 10-inch tube pan; line the bottom with parchment paper; set aside.
Preheat the oven to 325 degrees.
Combine the butter and cream cheese in the bowl of a mixer fitted with the paddle attachment; beat on medium speed until smooth.
Add the sugar, increase the speed to high; beat until light and airy, about 5 minutes.
Add the eggs, 1 at a time, beating after each addition and scraping down the sides of the bowl with a rubber spatula as needed.
Add the vanilla; the flour and salt all at once.
Beat just until incorporated.
Pour the batter into the prepared pan; shake lightly to even out the top.
Bake until the cake is golden brown and a cake tester inserted in the cake's center comes out dry, 1 hour 15 minutes.
Place the pan on a cooling rack; cool for 20 minutes.
Remove cake from the pan, and let it cool completely. Serve at room temperature.