Liquid chocolate is getting hard inside the cookies after baking. Baking temperature: 1st Zone: 161 °C, 2nd Zone: 183 °C, 3rd Zone: 165 °C. Baking time: 12.6 minutes.
Solution needed: How to get chocolate liquid after baking?
As far as I know it is not the baking time or baking temperature will have very little impact on chocolate getting hardened. It is the quality of the liquid chocolate you are filling. Should be made of high quality oil with very low melting point with stability (peroxide value, acidity). Secondly you can do with only dark chocolate liquid only. If you mix the milk solids more than certain percentage this issue will come. The flavour used in the liquid chocolate should be oil soluble flavour than water soluble. The best emulsifier in the liquid chocolate also contribute the liquidity of the chocolate after baking. Please check above parameters You will get some result I am sure.
Its my experience that the filling should not contain any dairy ingredients as the protein in the filling can absorb moisture from the biscuit dough during baking this is particularly noticeable at the interface between the biscuit shell and the centre filling
Did you use sugar or syrup in the filling chocolate?
Usually filling is getting hard during baking because wate from the dough is "reacting" with the sugar durin baking.
I assume you used soft fat in the filling chocolate
I’m not sure if you provided enough information to solve the issues of the hard filling you are experiencing. There are many factors beyond oven temperature. and bake time that could influence the final product hardness. We would need to understand what is the moisture and rH of the filling pre and post bake, what is the ratio of filling to base as starters . Is the filling a bake stable filling and formulated correctly to withstand baking while providing the shelf life you are looking for?