Combine the blood orange juice, blood orange zest, sugar, and eggs in a heavy-bottomed pan until thoroughly combined. Cook over low heat, stirring in the butter until it melts.
Cook for about 10 minutes, stirring constantly until the first bubble appears on the surface and it has thickened slightly. Strain through a fine-mesh sieve and let it cool completely. Press a piece of plastic wrap to the surface to keep a skin from forming.
In a small bowl, combine the flour, sugar, baking powder, baking soda, salt, and poppy seeds. Set aside.
In a medium bowl, whisk together the buttermilk, egg, melted butter, and vanilla extract. Add the flour mixture to the buttermilk mixture, and whisk until it's just thoroughly combined. Don't overmix or the pancakes will be dense! Let sit for 10-15 minutes until bubbles appear on the surface. (At this point, you will have a thick and bubbly batter. Don't stir it! Those bubbles are going to give you the fluffiest pancakes *ever*).
Heat a pan or griddle over medium heat, and grease the pan with a little bit of unsalted butter. Add 1/4 cup of batter to the pan, swirling it with a spoon to create a circle (it will be thick and won't spread on its own). Let cook until bubbles appear on the surface of the pancakes. Flip, and let cook until the pancake is lightly browned. Place cooked pancakes on a sheet pan in a warm oven. Repeat with the remaining batter.
Serve pancakes with the blood orange curd, whipped cream, and berries. Enjoy!