Taiyaki

Make the anko first. Rinse the azuki beans thoroughly, discarding any broken ones, then drain well.

Transfer the beans to a large pot and cover with water by 1 to 2 inches. Bring to a boil over medium-high heat.

Drain the beans in a fine-mesh sieve and return them to the same pot. Add fresh water to cover by 1 to 2 inches and bring back to a boil.

Place an otoshibuta (drop lid) on top, reduce heat to medium-low, and simmer, adding water as needed to keep the beans covered. The beans are done when one mashes easily between your fingers.

For tsubuan (chunky), drain the cooked beans in a sieve and return them to the pot over medium-low heat. For koshian (smooth), reserve some cooking liquid, drain the beans, blend in a food processor until smooth (add 1 to 2 Tbsp reserved liquid if needed), then return the puree to the pot over medium-low heat.

Add half the sugar (about ⅜ cup) and stir until dissolved, then add the remaining sugar. Stir in the salt.

Cook, mixing constantly, until the moisture evaporates and you can draw a line across the bottom of the pot with a spatula.

Transfer the anko to a flat baking sheet and let cool completely. You will use about 8 Tbsp for the taiyaki; refrigerate the rest in an airtight container for 3 to 4 days, or freeze in ~100 g portions for up to 2 months.

If making custard cream instead of or alongside the anko, cut the vanilla bean in half lengthwise and scrape out the seeds with a knife.

In a medium heavy saucepan, combine the 200 ml milk and vanilla seeds. Heat until almost boiling, when small bubbles form around the edges. Remove from heat and set aside.

In a medium mixing bowl, beat the egg yolks gently. Add the ¼ cup sugar and whisk until pale yellow, then add the 20 g cake flour and whisk until combined.

Pour a small amount of the hot milk into the egg mixture and whisk quickly. Slowly add the remaining milk while whisking.

Set a fine-mesh strainer over the saucepan and pour the mixture back through it. Cook over medium heat, stirring constantly with a silicone spatula, until thickened.

Keep stirring, scraping the bottom and corners. Continue until large bubbles appear on top, then let it boil while stirring for 1 minute. Add the butter if using.

Transfer the custard to a flat container and cover with plastic wrap placed directly on the surface. Cool over ice for about 30 minutes, then whisk until smooth. Store refrigerated for up to 2 to 3 days.

Now make the batter. Sift the cake flour, baking powder, and baking soda into a large bowl. Add the 3 Tbsp sugar and whisk thoroughly to combine.

In a medium bowl, whisk the egg. Add the ¾ cup + 4 tsp milk and combine well.

Pour the wet ingredients into the dry ingredients and whisk until just combined into a smooth batter.

Cover and refrigerate the batter for at least 1 hour to let the flour hydrate and the gluten relax.

Transfer the rested batter into a measuring cup for easy pouring (it yields about 1¼ cups).

Preheat the taiyaki maker over medium-low heat and brush the molds with neutral oil.

Pour batter until each mold is about 60% full. Add about 1 Tbsp of anko (or custard cream) in the center, then cover with more batter.

Close the lid, immediately flip the pan, and cook the first side for 2 to 2½ minutes.

Flip again and cook the second side for another 2 to 2½ minutes, until golden brown.

Remove the taiyaki to a wire rack and serve warm. To reheat cold taiyaki, toast in a toaster oven or oven until crispy outside.