Preheat the oven to 375ºF.
Sauté leeks, shallots, and salt in oil over medium heat until soft. Set aside to cool.
While onion mixture is cooling, make the Jalapeño crema by mixing all the ingredients in a bowl.
Once the onions are cool, mix with the onion mixture with the diced jalapeño, herbs and spices.
Separate the white from one egg. Whip until soft peaks form, then fold into the onion mixture.
Mix one whole egg, flour, baking powder and milk in a separate bowl until it forms a batter.
Combine the onion mixture with the batter and form into 4oz cakes.
Heat up oil in a large skillet. Fry each cake on high heat, 1-2 minutes per side.
Finish in a 375ºF oven for 10 minutes.
Let cool slightly before serving with jalapeño crema.