Preheat oven to 350. Line or grease your muffin tin and set aside.

Separate your eggs, putting the whites into the bowl of a stand mixer and the yolks in a small bowl. Beat the egg whites on high speed until soft peaks form. Scrape the egg whites into a small bowl and place in the fridge.

In the stand mixer, beat the butter and sugar together until fluffy, then add the egg yolks and mix until well-combined.

Dump in the flour, baking powder, baking soda, poppy seeds, lemon zest, and salt and beat for about 3 seconds, then add the buttermilk, and beat again for just a few seconds, then add the lemon juice and vanilla and beat just until combined.

Then get the egg whites out of the fridge, scrape them into the batter and gently fold them in with a rubber spatula until they are evenly incorporated.

Spoon the batter into the muffin cups, sprinkle with sugar (granulated or turbinado) and bake for 20-25 minutes until the edges are golden-brown and they spring back when gently touched.

Serve with lemon curd if at all possible.