I mean...Mocha is basically coffee and chocolate, yes? ...Yes...

Recipe (Vegetarian, Makes 24 Biscuits)

125g Butter (Softened at room temperature)
100g Light Brown Soft Sugar*
125g Caster Sugar*
1 Egg, Beaten
1tsp Vanilla Essence*
225g Self Raising Flour
1/2tsp Salt*
100g Chocolate, Grated
1tbsp Instant Coffee

1. Preheat oven to 180C

2. Cream the Butter and both Sugars together until it forms a paste.

3. Combine the Egg and Vanilla Extract until it forms a loose, wet mixture, then dissolve the Coffee in said mixture.

4. Sift in the Flour and Salt and fold it into the mixture, then the Grated Chocolate until a dough forms.

5. Take pieces from the dough and roll them into walnut-sized balls. Place them on a parchment-lined tray, allowing for about a 5" Diameter of space for each.

6. Bake for 8-13 minutes, depending on how you like them. Eight minutes yields softer biscuits, but ten to thirteen minutes gives a crunchier result.

7. Let the biscuits cool on the tray for a couple of minutes until they're firm/er, then transfer them onto a wire rack to cool completely.

Notes
- I've found that the specific sugars aren't all that important. I've used light brown, dark brown, muscovado...it's more of a flavour thing, I think.
- You don't have to use Vanilla Essence. I personally use Coffee Essence, I've also used Almond Essence in the past. Be adventurous!
- As long as you're using Salted Butter, you can forget about adding the 1/2tsp Salt.