Line an 8 x 8- inch pan with parchment paper and grease the paper with coconut oil or cooking spray.
Put measured coconut oil in the freezer for 15 to 20 minutes until it becomes solid all of the way through.
Put water in a saucepan over medium-high heat and allow to reach just a simmer. Add dates, and lower heat to medium-low. Cook until a paste is formed, for about 10 minutes. Allow to cool to room temperature. Add vanilla and stir.
Meanwhile, combine all of the dry ingredients in a large bowl.
Dice solid coconut oil to form pea-sized pieces.
Add coconut oil to dry mixture and combine with hands to form a lumpy, moist crust.
Add half of the oat crust mixture to bottom of baking pan and press with hands to flatten evenly.
Spread the date paste in an even layer over the crust.
Add the topping, gently flattening with hands. Bake until golden brown, about 35 to 45 minutes. Allow to cool and cut into squares to serve.