Preheat oven to 325 ° Fahrenheit.
Grab a cookie sheet and slather it with 2 Tablespoons melted coconut oil, completely coating the surface.
Place the dry ingredients into a high-powered blender: flax, raw cashews, cocoa, baking soda and sea salt. Blend for about 40 seconds, until the cashews are mostly powdered. Stop the motor, and use a spatula or wooden utensil to fold in the dry meal and larger pieces from the corners. Blend another 10 seconds.
Add egg, remaining coconut oil and honey, and blend again until mostly mixed. Use a spatula to fold in any dry spots from corners or edges. Blend again on medium-low speed until a fudgy batter is formed. Repeat one final time as needed, folding in any dry meal from the corners or bottom of the blender, then briefly blend again to incorporate.
This dough is very fun and easy to handle. It is almost non-stick! Place it in 6 or 8 pieces over the surface of the prepared cookie sheet and use your fingers to pat and shape it into a rectangle, about 10" by 13".
It will be less than 1/2" thick. Prick the dough all over with the tines of a fork, as you would a pie crust.
Bake 10 to 11 minutes, watching for the cookie surface to show subtle cracking and bubbles, similar to a pie crust, but don't let the edges get too dark or the cookie will break too easily when it's cut. Cool 8 to 10 minutes; then, using a long knife cut away the rough edges to create straight lines and slice the giant cookie into 12 rectangular shapes.
Carefully transfer cookies, using an offset metal spatula, to an un-greased cookie sheet. Refrigerate for 30 minutes. (If your ice cream is hard, you can place it in the refrigerator during this time to create a softer texture [that isn't melting as much as it would if held at room temperature].)
Use very scoop-able ice cream (softened slightly) to assemble ice cream sandwiches: place up to ¾ cup ice cream on each cookie, (shaping it with a spoon and butter knife works well) and top with second cookie, pressing down carefully to prevent the cookies from cracking, to seal the sandwich together. Freeze each sandwich as it's completed.
Chill 30 minutes or longer. Serve.