Heat olive oil (or water) in a wok or a large skillet over medium heat; add onion and garlic and sauté for about 2 minutes; stir from time to time;
Crush the minced tofu block with a fork; add it into the wok together with the simple tomato sauce and combine well;
Combine miso paste with 3-4 tbsp of water then add it to the tofu together with the rest of the filling ingredients, except for the carrot; combine well and cook for 7-8 minutes;
Fold in the grated carrot and cook for another 1-2 minutes, then turn off the heat;
Preheat the oven at 180°C;
Spread a marinara sauce layer on the bottom of the baking dish, then add a pasta layer (5 sheets); cover in marinara sauce and add half of the minced tofu filling;
Spread over the filling some marinara sauce and sprinkle 2-3 tbsp of nutritional yeast;
Add another pasta layer, and repeat with the rest of the ingredients;
Bake the lasagne at 180°C for 50-60 minutes, until the pasta is soft enough;
Remove the dish from the oven and allow lasagne to cool for a few minutes before serving.