Combine unsweetened almond milk, sweetener, and cashews in a small, deep saucepan. Bring the mixture to a simmer over medium heat, stirring frequently, until steam rises, then lower the heat.
Continue simmering on a low heat for about 5 minutes, but do not allow it to boil. This will soften the cashews, making them ready for blending with the milk.
Reduce the heat to low, and grind the cashews in the milk using an immersion blender until thoroughly blended and frothy.
You may need to move the immersion blender slightly up and down while keeping it immersed in the milk to catch any large pieces of cashews at the bottom.
While keeping the heat low, use a sieve to add matcha powder to the milk to help break up any lumps in the matcha that may have formed during packaging.
Use the immersion blender again to mix everything thoroughly and create a smooth texture. You will notice that it transforms into a delightful light green and frothy texture.
Once the latte is smooth and frothy, turn off the heat, pour it into your favourite mug, and enjoy!