Preheat your oven to 350°F (176°C). In a large bowl, use an electric mixer to beat the butter and cream cheese together until smooth and well combined. Add the sugar and continue beating for about 5 minutes, until the mixture becomes light and fluffy. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract. With the mixer on low speed, add the flour and salt in two parts, mixing just until everything is incorporated—do not overmix.

Generously spray two 8½-by-4½-by-2½-inch (21 cm by 11 cm by 6 cm) loaf pans (each holding about 1½ quarts) with nonstick cooking spray. Immediately divide the batter evenly between the prepared pans. The batter will come close to the top, which is expected. Gently tap the pans on the countertop to release any large air bubbles.

Bake the cakes for 60 to 75 minutes, or until the tops are golden and a toothpick inserted into the center comes out mostly clean. If the tops begin to brown too quickly, loosely cover them with foil to prevent overbaking.

Let the cakes cool in the pans for about 10 minutes. Then carefully turn them out onto a wire rack and allow them to cool completely, placing them top-side up.