In a large lidded jar (I used a mason jar), combine the coffee grounds and water. Let sit out at room temperature for at least 12 hours or overnight.
The next day, strain twice: first through a mesh strainer, and then through a coffee filter (to catch the silt). Coffee concentrate is now ready to use.
To use coffee, combine with water at a 1:1 ratio in a cup filled with ice. Add Sweet Vanilla Cream, if desired. (recipe follows)
In a small microwave safe cup or bottle, add the vanilla, sugar, and cream. Microwave for 1 minute and stir to dissolve sugar. Microwave for 30 seconds longer if needed.