Do not worry about the weight part if the baby is active and achieving milestones. Include good fats like ghee, coconut oil, unsalted butter, potatoes, Paneer, eggs, avocado etc

Hey Arti, add some weight gaining recipes to her diet. Like paneer recipes, dry fruits badam pista cashew raisins laddo, potato, sweet potato, non veg, egg, urad dal laddoos, along with her regular food. I am trying these items with my baby. I am suggesting you with my experience.