Advice on body weight 70kg to 80kg

Hi

I was 65kg 6 months ago and put on 70kg using a good diet plan and weight training, I'm doing more weight training per day and per hr , I'm trying to achieve a body weight of 80kg, but struggling, I worked out that I need to take 3500cal a day to get that goal, and I'm struggling to do that and I hate force feeding myself, I get about 2500cal a day just eating different food types, was thinking I've adding a weight gain shake to my diet and training plan, any advice please