Grill the eggplants: Cut the eggplants into 0.5 cm strips and cook on a slightly oiled grill or in the oven. They do not need to cook a lot, just enough that they are slightly charred and that they bend. Alternatively, brush with olive oil and roast them at 220C/425F (220° C) for 10-15 minutes.
If making the homemade tomato sauce, heat up the olive oil in a pan, add diced onion and garlic, let them cook for 5-8 minutes then add the tomato passata and let it cook on low heat for 20 minutes.
Make the soy milk ricotta: to make the soy milk ricotta, pour the soy milk in a pot, let it reach boil then remove from the heat. Add the lemon juice, mix with a wooden spoon and let the milk curdle.
Place the milk in a cheesecloth bag over a sieve and bowl and squeeze the bag to remove excess water then leave it with a heavy weight to drain more if you have some time, about 10 minutes.
Combine the ricotta with olive oil, salt, pepper, oregano and some water to make it smoother.
Combine the eggplant rolls: Take each eggplant strip, spread the ricotta all over the strip, then roll it on itself, repeat for the rest.
Bake: On a baking tray, spread half of the tomato passata on a thin layer, then place all the eggplant rolls in a line, and cover with the rest of the passata. Cook in the oven at 190C (fan) for 25 to 30 minutes. If you pre cook your tomato passata, then it can stay in the oven less, like 15-20 minutes