1. Prepare a 9 x 13-inch (23 x 33-centimeter) baking pan.
2. Combine the oat milk and two tablespoons lemon juice in a shallow bowl and quickly
submerge one ladyfinger at a time in the mixture, being careful not to leave it in the liquid for too long.
3. Place the ladyfingers two across into the pan and create two rows, about 12 fingers per
row. Spread or pipe a layer of lemon cream over the ladyfingers. Spoon a thin layer of blueberry coulis onto the cream, spreading gently from edge to edge.
4. Repeat with another layer of ladyfingers, cream, and blueberry coulis.
5. Add a final layer of ladyfingers and cream, then spoon small dollops of blueberry coulis in a random pattern on top of the cream.
6. Add fresh blueberries all around, if desired.
7. Using a toothpick, create decorative swirls with the coulis into the cream.
8. Create a tent out of aluminum foil to cover the tiramisu, and place in the fridge for at least eight hours or overnight. Alternatively, you may freeze the tiramisu and simply defrost overnight in the refrigerator, adding the fresh blueberries just before serving.