Gradual light increase

Re: gradual light power increase within 15 min with a timer and one room

Guys. I have created a Room called WAKE UP. Secondly I have created a Timer for this room to wake me up at 7 morning. Now I would like to make it possible that these lights will turn on gradually and slowly during 15 minutes…instead of having them turn on immediately. There is a possible snozz option but cannot find the gradual light increase for this function. Please help. Cheers Mike