Do you mix baby cereal with purée?

Like rice, oatmeal, whole wheat, whatever you use(d).

Can I mix it with my baby's fruits/veggies instead of just milk?

(This is only for people who do/did use cereals. If you skipped them altogether, I respect that and kindly ask that you don't lecture me about it. My baby's doctor said we need to incorporate more because she needs to gain weight/needs more iron/etc).