Eat more for muscle gain

Hello everyone :)

So I'll jump right into it ^^ my goal has been for the last two months to gain mass in order to have a bigger butt and some more muscle (I know it's hard but gotta try :)

So I have been eat peanut butter with brown rice and quinoa tortilla for breakfast every morning, and eating nuts (almonds/pecan) around 11am and 5pm . After my workouts, I eat a salad (avocado/tomatoes/cucumber/beetroot/ with olive oil and balsamic), and then I'll have a shake with protein powder (coconut milk/some pecan nuts, half a banana and some cinnamon).

But all it does is adding fat to my tummy :////

Any suggestion on what I'm doing wrong and should do?

Thank you very much :)