There are many strategies to assist the user in pervasive environments. In some cases, the user has to achieve a goal according to a plan known by the environment. We address the issue of enabling the environment to be aware of which task of the plan is currently on-going. We present a strategy that makes use of temporal patterns called memory chronicles and that watches events that occur in object memories to recognize if they match any memory chronicle of any task of the plan. We take the example of a smart kitchen where tools and ingredients are considered as objects with memories and where the cook reproduces a recipe according to a recipe plan known by the kitchen. We explain how the kitchen makes use of memory chronicles to applying cooking task recognition and guide the cook through the recipe plan.