I have done chawanmushi before, and this is quite similar to that as well. The idea was to do this baked or steamed uni custard(in an egg shell) with a light buttermilk foam-type of thing, and on top of that, some fresh uni, just to tie it all in together. In the past, I have done farm egg-types of amuse bouches(fun fact, my Masterchef bestie Bri and I served those at our second pop-up in Dallas!), so I was familiar with the concept of cutting the tops of eggs off, removing the inner membranes, and using the shells as serving vessels. To the point where I literally do that with all of the eggs I cook with, just to save the shells for other things. Such as this dish. I wanted to make this uni custard in particular for Father’s Day, since my dad loves uni(sea urching) – whenever we would go to sushi buffets, they would always have a “one uni per person” rule, so my dad would make me and my sister get him uni every time we would go to our own food. When we went to Hawaii, my dad even went diving for fresh sea urchins! So using it here definitely is an homage to him.
For the components, we have an uni custard made with uni, eggs, and dashi. I couldn’t find a way to steam the custards in the egg shells, so I opted to bake them, in a similar fashion to flan. I paired that with a yuzu buttermilk, made by infusing yuzu juice with cream, then whipping that with a little creme fraiche so that you have this light, sour mousse that contrasts the salty-sweet egg custard. The fresh Santa Barbara(which are plump and sweet compared to the Maine variety) uni on top of just used to tie in the fact that it is an uni custard. For mine, I served the egg shells in a bowl lined with rice, since the rice helps hold up the egg for presentation reasons. However, if you want to use egg cups, that would work even better! Keep in mind that the recipe is specifically for the custard being baked in an egg shell. If using a ramekin, expect the custards to take anywhere from 20 to 30 minutes to bake in the oven!
For the custard:
a pinch of salt
2 pieces(tongues) of uni
150g eggs(about 3 eggs)
Bring kombu, water, and salt to a simmer on low heat for about 10 minutes. Remove the kombu, and puree the liquid with the uni and eggs. Pass through a sieve lined with a cheesecloth or paper towels into a bowl(this step is to remove both lumps and air bubbles in the custard!). For the containers, I re-used egg shells, and I baked them at 350 degrees F for 12 minutes. You want the custard to just slightly wobble. Cool down the custards in an airtight container before attempting to assemble.
For the yuzu buttermilk:
2 tbsp yuzu juice
1/4 cup heavy cream
2 tbsp creme fraiche
a pinch of salt
Mix yuzu juice with the heavy cream first. Allow that to sit for 10 minutes at room temperature. Then whisk with the creme fraiche and salt until it forms soft peaks – be very careful, as this mixture can split and overwhisk very easily! Transfer to a piping bag and store in the refrigerator.
Pipe the buttermilk into the custard and finish with fresh pieces of uni.