Remove featured image as header image.

Hello, I have a quick question I’m hoping someone with a bit more experience can answer for me. I’m helping a friend build herself a website for her hot sauce and we are using portfolio post type to display pictures and recipe ideas. When we select a featured image it uses that image as the header for the post. Can we turn that off? It doesn’t work so well for the pictures we are using.

For example: here we see the top of a big ugly hot dog across the header of the page.

We still want to be able to set a featured image so we can have an image show up on the portfolio section of the homepage, we just don’t want that image also used as a header image for the page.

P.s. I figured out how to hide header images in posts but not portfolio posts. Any help is appreciated.

The page I need help with: [log in to see the link]