1. In a medium microwave-safe bowl, whisk together cocoa, sugar, hot water, and corn syrup until evenly blended. Whisk gently at first, as cocoa powder can be dusty. Microwave on high for 1 minute and whisk again. Heat for an additional 45 seconds, until mixture is steaming hot and smooth.
2. Add chocolate chips to the cocoa mixture and stir until they begin to melt, about 1 1?2 minutes. Microwave the sauce for 30 seconds. Stir well until all the chocolate has melted and mixture is smooth. Heat for a few more seconds if needed. Stir in the vanilla and peppermint extract.
3. Divide sauce among 4 (8 oz.) glass jelly jars. Place lids on jars after filling with sauce.
4. Allow sauce to cool to room temperature, about 45 minutes, then refrigerate until needed. Finished sauce can be stored in a sealed container, refrigerated, for up to 1 month. Cold sauce will be quite thick; reheat in the microwave for 10 to 30 seconds on high before serving.
Source: Hannaford fresh Magazine, November - December 2009