Mentaiko is a sac of wonderfully delicious cod roe. It's full of flavor and texture, literally bursting at the seams with all that goodness. You can find it at any Japanese market. Back when I used to visit Saint Mark's in NYC, that entire row of Japanese izakaya/yakitori's they had mentaiko mayo for dipping pipping hot fat french fries in and I kind missed that, so I made my rendition of it w/ my other favorite dish, carbonara. Yum. Drooling here just thinking about it again. Really simple and easy to make.
1. Whip up 2 yolks of egg in a mixer
2. Slowly add 1/2 cups of your choice of oil (I used olive oil)
3. Let is beat for about 20 mins, basically it ends up with the consistency of store bought mayo, but much much better in flavor and color (bright yellow)
4. Add in a 1Tbps of hot water to lighten the color, you don't have to do this part if you want to keep it fuller and yellow
5. Add in half slice of lime and cara cara oranges
6. Create a garlic paste by pressing your knife blade on the minced bits, add this to the mixture
7. Fold in the mentaiko eggs without the sac
8. Add cooked pasta a bit al dente since you want the pasta to soak up all the yummy juices
I added a few sauteed portobello mushrooms to additional texture to it and ate all of it with a few pickled string beans. Yum yum. The acidity of the lime and the pickled string beans really compliment the fatty velvety smoothness of the carbonara. Hope you make it too and enjoy it just as much as I did.