You can make these cookies ahead of time and keep in the freezer until needed.
Place flour, salt, cinnamon and baking soda in a large bowl and set aside. Cream butter and sugars in mixer. Add eggs and vanilla paste (or extract), mix until well combined. Slowly add flour mixture and whole oats, mix well. Add chocolate chips and pecans, fold in by hand. Place by large spoonfuls onto parchment covered cookie sheet and bake for 9-11 minutes. Allow cookies to cool, then freeze in a closed container.
Allow to sit on counter for 30 minutes. When ganache is thick it's time to assemble!
Place frozen cookies upside down on cookie sheet and place a spoonful of ganache on each cookie. Place a scoop of ice cream on one cookie and then carefully top with another so ganache is on the bottom and the top. Serve immediately or quickly wrap in wax paper, place back in a sealed container and freeze until ready to eat.