Put the water in a ramekin and sprinkle with gelatin and allow it to hydrate (about a minute). Add the shiso and microwave until it comes to a boil (about 30 seconds to 1 minute). Allow the mixture to steep until it cools down a bit. Add the lemon juice then pass the mixture through a tea strainer into 2 ramekins. Coat the sides of the ramekin with a thin layer of the mixture then refrigerate until set.

Cut the tofu into 2 large blocks, place them in a small saucepan and add enough water to cover. Bring the water to a boil, turn down the heat and simmer for a few minutes. Drain and allow the tofu to cool to room temperature. Put each block into a cheese cloth (or several layers of paper towels), mash it up a bit, then squeeze out most of the moisture. You should be left with dryish white curds.

Add the curds to a food processor along with the tahini, salt and lemon juice and process until smooth, scraping down the sides of the bowl at least once.

Using a rubber spatula, spread the mixture a small amount at a time into each ramekin smoothing off each layer and building it up slowly to avoid air pockets. Refrigerate for at least an hour to set (should be the texture of cold cream cheese).

Remove the ramekins from the fridge and place briefly in a hot water bath to release from the ramekin and invert onto a serving plate. Serve with crackers or bread.