What is good healthy food for my squirrel friends?

There’s a tree with a big knothole in front of my place.

One day on a whim, I threw some peanuts in the shell into the abyss. The next day, the peanuts were gone.

I kept up the habit. I feed them a lot of peanuts.

Now the squirrels know me. I have squirrel stalkers! Whenever I“m around the building, they follow.

What should I feed my squirrel friends? More peanuts? Broccoli?

What?