Preheat oven to 325 F. Line the bottom and sides of the cake pan with parchment paper.
Melt butter and whisk it into the ricotta. Add the four egg yolks and Elderflower Cordial, whisk, and then add the the sugar, zest, poppyseeds, and vanilla bean. Beat with a hand mixer until well combined. Add almond flour and whisk again.
In a separate bowl, peak egg whites until very still. Then paddle the egg whites into the cake batter, adding only 1/3rd of the eggs whites at a time to the batter becomes silky and voluminous.
Add batter to lined cake pan and bake for 40-60min, depending on cake pan size.