Whisk together the flour, baking powder, and salt unit well
blended. With an electric mixer, beat the cream cheese and butter
until slightly fluffy. Scrape the sides of the bowl well. And the
eggs one at a time, beating until blended before adding the next.
With the mixer on low, add the flour, vanilla, lemon zest and mix
until almost incorporated but not quite.
Scrape the batter into the loaf pan and bake in the middle of the
oven until the cake is golden brown and a toothpick comes out
with just a few crumbs clinging to it when inserted in the center,
60 to 65 minuted if using fresh berries, 75 to 90 minutes if using
frozen berries. Let the cake cool for about 15 minutes and then
invert the pan and lightly tap it to release the cake. Cool
completely on a rack before serving.