Preheat oven to 350ºF/160ºC and line two large baking trays with non stick baking paper.
Whisk (or sieve) together flour, cocoa, baking powder, spices and salt.
With a whisk attachment on the an electric mixer beat together eggs until frothy then slowly add sugar. Beat until pale and thick.
Slowly drizzle in the olive oil followed by milk and vanilla.
Using a wooden spoon, add the flour mixture in two lots, stirring until smooth.
Stir through the walnuts and mini choc chips.
The dough will be soft and sticky. Cover the bowl with plastic wrap and allow the dough to rest for 20 to 30 minutes.
Take a rounded teaspoonful of the dough and roll between your palms into a ball. If the dough is impossible to roll add a spoonful of flour but not a lot - this dough is meant to be sticky. Check the photos above to compare with your dough.
Place the balls on the prepared trays allowing room for spreading and rising.
Bake for 10-12 minutes. Don't over bake - these are meant to be soft and moist. The cookies will rise and form a few cracks. Cool on the trays for a few minutes before transferring to wire racks to cool.
Spread a small amount of icing on each cookie and decorate with coloured sprinkles. Allow icing to set before serving or storing.
Icing
If the sugar has lumps, sieve before using.
Mix the powdered (icing) sugar and milk together to form a thick but spreadable icing. Add more milk if needed.
Notes
If you prefer a spicier cookies, slightly increase either or all of the ground cinnamon, grated nutmeg or ground cloves.
Use light flavored or regular olive oil instead of extra virgin olive oil.
Tips for success
It's really important not to over-bake otherwise they will be dry. These cookies should be soft and moist.
Use large eggs.
Fresh walnuts for best results.
Be sure to rest the dough before forming cookies and baking.
Use a cookie scoop or two teaspoons to help shape the dough.
Lightly oil your hands to help the dough not stick too much. It will be a bit messy but that means that your cookies will be deliciously moist!
How to storeStore at room temperature in an airtight container with non stick or wax paper between the layers for 5 days.How to freezeYes! Freeze in an airtight container for up to one month (possibly longer). When thawing, don't remove instead thaw cookies completely in the container.These cookies have be adapted from a recipe for Roman Chocolate Cookies in Greg Patent's cookbook "A Baker's Odyssey".