You can use the technically - not - paleo (but dairy - free and soy - free) Enjoy Life dark chocolate morsels or other purchased chips of your choice, OR you can make your own homemade dark chocolate with this recipe from Bakerita. (paleorunningmomma.com)
I usually just mix it with almond milk and top with dark chocolate morsels. (lifehacker.guru)
Dark Chocolate Chip Cookies: Substitute 1 (12 - ounce) package dark chocolate morsels for semisweet chocolate morsels. (myrecipes.com)