In a tall and narrow container (something like a tall mason jar with a wide opening) add the soy milk at room temperature,the lemon juice and a pinch of salt.
With a hand blender, start blending into the soy milk. Then add the oil in a steady stream, very slowly. NOT all at once. Keep blending at all times.
Drizzle the oil very slowly while blending and while moving the blender up and down into the soy milk.
Keep adding the oil, very slowly, until you run out of oil. Blend while moving the blender up and down until you reach a thick, creamy, consistency.
Store the margarine in the refrigerator in a glass jar for up to 5 days. Use for cakes, biscuits, cookies, and crispy preparations. You can also use it as a spread on toasted bread.