1. 1. Soak the cashews overnight or for at least 4 hours. Drain and blend them with 1/2 cup of water, nutritional yeast, and white vinegar until smooth and creamy.

2. 2. Slice the leeks and sauté them in 2 tablespoon of vegan butter over medium heat for 8-10 minutes until soft. Season with salt and pepper.

3. 3. In a bowl, combine 1 1/2 cup of flour and 1/2 teaspoon of salt. Cut in 1/2 cup of vegan butter until the mixture resembles coarse crumbs. Gradually add water, one tablespoon at a time, until the dough comes together. Chill for 20-30 minutes.

4. 4. Preheat the oven to 350°F (175°C).

5. 5. Roll out the chilled dough and fit it into a tart pan. Blind bake for 10-12 minutes until lightly golden.

6. 6. Spread the cashew mixture evenly over the baked crust and arrange the sautéed leeks on top.

7. 7. Bake for 20-25 minutes until the filling is set and the edges of the crust are golden brown.

8. 8. Allow to cool slightly before slicing and serving.