Puree butternut squash with blender and set aside to let cool

In a small saucepan, heat cream, milk, nutmeg, cinnamon, ginger and vanilla to a simmer

Meanwhile, in a separate bowl, whisk yolks and sugar until pale yellow

Add a cup of the hot cream mixture very slowly into yolks while continuing to whisk

Then add yolks and cream back to saucepan and keep stirring over low heat

Mixture should thicken in a few minutes, then turn off heat and incorporate into squash puree

Preheat oven to 375 degrees, making sure the rack is near the bottom

Place a baking sheet in the oven

Butter your ramekins and dust the insides and rims with sugar

Then take egg whites in a clean bowl and whisk until glossy

It should form stiff peaks when you remove your whisk from the bowl, and should be able to hold the weight of an egg

Use a spatula to combine the egg whites scoop by scoop into the squash mixture, making sure they form a fully homogeneous mixture, but do not overmix

Carefully scoop your mixture into the ramekins up to the rims

Bake on lower rack for about 25 minutes, or until tops are golden brown

They should rise, but with firm tops and jiggly centers