Make the cake:
Position a rack in the center of the oven and heat the oven to 350ºF. Butter and flour two 9x5x3-inch loaf pans (or eight 5-3/4x3-inch mini loaf pans, each with a 2-cup capacity). Tap out any excess flour.
In a medium bowl, sift together the flour, baking powder, and salt; whisk in the poppyseeds. Put the sugar and orange zest in a food processor and pulse for 20 seconds. (If you don’t have a food processor, omit this step and blend the zest into the flour.)
With a stand mixer (use the paddle attachment) or a hand mixer, beat the butter and cream cheese in a large bowl on medium speed until smooth and creamy, about 2 minutes. Add the sugar and beat until light and fluffy, about 1 minute. Beat in the whole eggs one at a time, stopping the mixer to scrape the bowl after each addition. Beat in the egg yolks and vanilla. With the mixer on low speed, slowly add the flour mixture. Stop the mixer at least one last time to scrape the bowl and then beat at medium speed until the batter is smooth, about 10 seconds.
Spoon the batter into the prepared pans, spreading it evenly with a rubber spatula. Run a knife through the batter to eliminate any air pockets or tap the pan lightly against the counter. Bake until a wooden skewer inserted in the center comes out with only a few moist crumbs clinging to it, about 50 minutes. (25 to 30 minutes for mini loaves). Set the pan on a rack to cool for 10 minutes.
Make and apply the glaze:
Tip:To wrap the glazed cakes for gift giving or freezing, spread a small amount of vegetable oil onto a sheet of plastic wrap with your fingers and place the oiled side against the cake.
Strain the orange juice into a small saucepan and bring to a boil over high heat. Stir in the sugar and continue to cook until the mixture thickens and is reduced to a scant 1/2 cup, 3 to 4 minutes. Remove from the heat and stir in the liqueur. Remove the cake from the pan. Brush the tops and sides of the cake with the glaze. Repeat brushing every few minutes until all the glaze has been used. Serve the cake at room temperature.