Begin by soaking the cashews in boiling water for 1-2 hours, or ideally overnight for a creamier texture. After soaking, drain them thoroughly.

In a high-speed blender, combine the silken tofu, your choice of plant-based milk, drained cashews, sugar, lemon zest, lemon juice, vanilla extract, and a pinch of salt. Blend until smooth, approximately 1-2 minutes.

Taste the mixture and adjust flavors with more lemon juice or sugar as desired. Blend briefly to incorporate.

Add cornstarch or agar agar to the blended filling, and pulse until mixed. Transfer to a heavy-bottomed saucepan. Heat over medium heat, whisking frequently, until bubbling, around 5 minutes.

Once thickened, remove from heat and pour into prepared crust. Allow to cool at room temperature before refrigerating uncovered for at least 3 hours.

Serve chilled, optionally garnished with fresh berries or a fruit compote. Store leftovers in the refrigerator for up to 5 days.