The trick to making this is to spread the sauce on thickly and to thoroughly toast thte bread. You can also use spicy mentaiko! If you chop the toast up into bite-sized pieces, it makes a good appetizer with drinks.
Remove the membrane from the tarako sack, and place 1/2 the tarako in a bowl. Add a volume of mayonnaise equal to the volume tarako.
This tastes so much better if you spread the sauce on really thick.
Toast the bread, and it's done. Since this is quite salty, I suggest serving it with something that's not salt-heavy!
In Step 1: This is also delicious if you reduce the amount of tarako and mayonnaise in Step 1 and mix in some pizza cheese! The cheese is better mixed into the sauce rather than sprinkled on top.
Story Behind this Recipe
I saw sliced baguettes topped with tarako at a bakery sold as "Tara-Mayo."
I don't really like baguettes, so I decided to try making it myself with sliced bread.
I recommend spreading a decent amount of the sauce thickly on the bread, as opposed to a thin layer. Toast it until the surface of the taiko becomes crispy, so that it breaks when you bite into it. This goes amazingly with beer! Use cheap tarako.