Preheat oven to 350*F.
In a mixer with paddle attachment, cream butter and sugar together.
Add molasses and vanilla and blend until mixed.
In another bowl mix flour, spices and baking soda.
Gradually add dry ingredients to wet ingredients until completely mixed, making sure to scrape the bowl and fully incorporate the wet with the dry. This is important to prevent pockets of wet ingredients burning during baking.
Using a small cookie scoop, scoop dough and roll into sugar. Place cookies on a parchment lined cookie sheet allowing 2" between each cookie.
Bake cookies for 8 mins. Cookies will be soft so let stand to cool before transferring to a container.
In a mixer with whisk attachment, cream butter and shortening together.
Add flavouring oil and cinnamon and continue to mix.
Gradually add icing sugar and use holiday nog to soften the icing. You may need to add a little more to soften if required.
Fill icing into a piping bag fitted with a 1A tip. Pipe a small portion of icing to the centre of the cookie and use another cookie to flatten the icing as a sandwich.
Store in an air tight container for up to 1 week.