Prepare the molds: Rinse your molds with cold water and leave them slightly wet. This helps the set cake release cleanly.

Mix the base: In a small saucepan, whisk the agar-agar powder with the sugar. Add the water gradually while whisking to avoid clumps.

Heat gently: Bring the mixture to a gentle boil over medium heat, stirring often. Once it starts bubbling, cook for 1–2 minutes until the agar fully dissolves and the liquid looks clear.

Flavor lightly (optional): Remove from heat. If you’re using a drop of yuzu or vanilla, stir it in now. Keep the flavor subtle.

Pour and cool: Carefully pour the liquid into the molds. Skim any bubbles on top with a spoon for a glassy finish.

Chill to set: Let the molds cool at room temperature for 10 minutes, then refrigerate for 1–2 hours until fully set and bouncy.

Make quick kuromitsu (if not using store-bought): Simmer 1/4 cup dark brown sugar with 2 tablespoons water until syrupy, 3–4 minutes. Cool completely.

Unmold: Gently press the edges and release the cake onto a chilled plate. Handle with care; it’s delicate.

Serve: Dust with kinako and drizzle with kuromitsu. Serve immediately for the best texture.