Put the flax seeds in a bowl with 4 T. (60 ml) filtered water and set aside.
Cover the cashews with filtered water and let sit about 30 minutes.
Drain the cashews and put them in a blender or food processor.
Add the soaked flax seeds, lemon juice, and oil. Blend until it is a smooth consistency. (If you have a wimpy blender, you may need to add some filtered water to help it along.)
Add the tofu a large chunk at a time, blending well after each addition.
If you are making lasagne, you can add 2 cloves of garlic and a generous pinch of dried basil and oregano to the blender.