Add almonds, cashews, macadamia nuts, and dates to a large jar or bowl. Cover with water and soak overnight (or for at least 6–8 hours).
Transfer soaked nuts and dates (along with their soaking water) to a blender. Add 1.5 cups fresh water and vanilla extract.
Blend on high for 90 seconds or until smooth and creamy.
Strain the blended mixture through cheesecloth or a nut milk bag into a bowl or pitcher. Discard or save the pulp for baking or smoothies.
Pour the strained milk into a small saucepan. Heat gently to 160°F, holding that temp for about 15 seconds to lightly pasteurize.
Let cool completely. Transfer to an airtight bottle or jar. Store in the fridge for up to 5 days. Shake before use.
Notes
Storage: Store in an airtight bottle or jar in the fridge for up to 5 days. It separates as it sits since there are no stabilizers, so shake well before pouring.