Add macadamia nuts to a food processor or a high-speed blender along with lemon juice, nutritional yeast, garlic salt and 1/4 cup (60 ml) water.
Mix/blend, scraping down sides as needed. Then add more water 1 Tbsp (15 ml) at a time until a thick paste forms. I find I get the best texture results with a food processor, but in a pinch, a blender can work too. It just might require more work!
Taste and adjust flavor as needed, adding more nutritional yeast for cheesy flavor, salt for saltiness, lemon juice for brightness, or garlic salt for garlic flavor.
Blend again to combine. If adding herbs or spices (like red pepper flakes) add at this time.