ぱすてるキッチン ～ブルーベルへようこそっ!～

Main character is trusted to run restaurant while owner is abroad. But it turns out that master also applied to participate in the cooking competition contest, and now it's also under full protagonist's responsibility. The problem is that he's only good in washing the dishes, but not cooking. So he has to rely on his childhood friend. For that he organizes special training sessions at nights. Now that there are new part-time workers arrived protagonist extends his training sessions further.

[From vndbreview]