Yes, you can add anything you think the birds would like (seed, nuts, small pieces of fruit). I used to make my own - re-using the plastic forms from commercial suet cakes over and over. I didn't follow a specific recipe, just melted lard and some peanut butter together then mixed in cornmeal and mixed seed. I did not add sugar. Grocery stores used to sell lard very inexpensively, but lately it is a wash costwise and I can usually find commercial suet for 69 cents or so, at which time I buy it by the case. I did enjoy making my own though. Maybe buying lard through a meat processor would be more cost effective.
