In a bowl, combine walnuts, pecans, dates, and one cup of water. Let soak for at least 4 hours. However, if you're pinched for time, soak nuts and dates with one cup of boiling water instead, for about 10-15 minutes.

In a blender, add nuts, dates, the water it was soaking in, two additional cups of water, plus the cinnamon. Blend on high for at least two minutes, or until mixture is smooth in the blender.

Line a large bowl with a nut milk bag. If you don't have one, you can also you a cheesecloth or even a fine mesh sieve. Just note that using a sieve may not result in a super-smooth milk.

Once all of the mixture has been poured, squeeze the liquid out into the bowl.

Once you've squeezed out as much liquid as you can, transfer the milk into an airtight container. I like to use mason jars. The milk can be used immediately, or can be kept in the refrigerator for up to a week.