With your stove flame turned off, add the plant-based milk to a pot, along with the other ingredients except for the biscuits, the mint leaves, and the peaches.
Mix very well until all the cornstarch dissolves completely.
Turn on the heat, stir until the cream thickens up.
Remove the cream from the pot, add to a bowl, cover with a cling film making sure the film touches the surface of the cream, this will prevent forming a hard skin on top of the cream. Put it in the fridge.
Remove the peaches from the syrup and chop them in medium pieces, leave a few long ones for garnishing the tiramisu later. Do not discard the syrup.
On a 26 X 18 X 6 cm dish, add a layer of the cream, dip both sides of the biscuits in the peaches syrup, then layer them on top of the cream, followed by a layer of the peaches on top of the biscuits.
Repeat this process until you have filled to dish completely, finish it with a layer of the cream and garnish with the long peaches and a few mint leaves.
Put the tiramisu in the fridge for at least 5 hours. Serve it cold!