Preheat oven to 350 degrees with the oven rack in the middle. Line a baking sheet with parchment paper.
In a medium size mixing bowl, whisk to combine the flour, poppy seeds, baking powder, baking soda, and salt. Set aside.
In a separate medium size mixing bowl, whisk to combine the 2 eggs + 2 egg yolks, sugar, orange zest and orange juice until well combined, about 1 minute.
Add the wet ingredients to the dry ingredients, fold until just combined. Will look dry.
On the parchment lined baking sheet, press the dough into a roughly 11" x 3" loaf. Pat down until they are about 3/4" thick.
Bake for 35 minutes, turning the cookie sheet half way thru baking. Remove and allow the loaf to cool for 10 minutes.
Lower the oven temperature to 325 degrees.
Once the loaves are cool enough to handle, use a serrated knife to cut ½" thick slices. Bake the slices another 15 minutes, turning each slice half way thru baking. Remove from the oven and allow to cool completely.