Preheat oven to 325°F (160°C). Grease and flour two 5x3-inch mini loaf pans or spray with floured cooking spray. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment (or a large mixing bowl with a hand mixer), combine the eggs, granulated sugar, softened butter, softened cream cheese, and vanilla extract. Beat on medium-high speed until light and fluffy, about 5 minutes.

Scrape down the sides of the bowl. Add the all-purpose flour, baking powder, and salt (if using). Mix on medium speed until just incorporated. Do not overmix.

Divide the batter evenly between the prepared mini loaf pans. Bake for 45 to 50 minutes, or until the cakes are domed, golden brown, springy to the touch, and a toothpick inserted into the center comes out clean. Rotate the pans halfway through baking if necessary.

Let the cakes cool in the pans for about 15 minutes before inverting them onto a wire rack to cool completely.

While the cakes are cooling, prepare the glaze.

In a medium bowl, combine the softened cream cheese, softened butter, vanilla extract, and confectioners' sugar. Beat on medium-high speed until the glaze is smooth and silky. Add more confectioners' sugar if needed to reach your desired consistency.

Once the cakes are completely cooled, drizzle the glaze over the tops of the loaves or spread it on the interior of sliced cakes. The glaze can be stored airtight in the refrigerator for several weeks.