In an airtight container, soak dates in rum (or rum extract + 1/2 cup water) for at least 5 hours, preferably overnight.
Preheat oven to 325°F.
Using an electric mixer with paddle attachment or a hand held mixer, cream butter, shortening and sugar together until light and fluffy (about 2-3 minutes).
Add egg and vanilla. Mix. Scrape sides of bowl then mix again.
In a separate bowl, combine dry ingredients together (flour, oats, salt, cinnamon, cloves, nutmeg, and baking soda).
Add dry ingredients to sugar mixture. Mix only until dry ingredients are almost incorporated. Scrape side of bowl. Add rum-soaked dates (plus any additional liquid). Mix for an additional 15-30 seconds. Mixture should be soft, sticky but still hold it's shape.
Use a size 20 scoop (about 3 1/2 tablespoons) to shape dough. Place dough on prepared cookie sheet lined with parchment paper. Place 6 cookies on sheet OR use size 40 scoop ( about 2 tablespoons) placing 12 cookies per sheet.
Bake at 325°F: size 20 large cookies for 12-15 minutes and size 40 small cookies for 8-9 minutes. See notes*