If you said “After dinner can we have ice cream for desert?” I know what you mean, even if your pronunciation is incorrect.
Here is the sound each word makes:
dessert – DIZ-ZURRT
“After dinner can we have ice cream for dessert?” DIZ-ZURRT
desert – DEZ-IRT
“My student used to live in California, and he often went to the Mojave desert with his family.” DEZ-IRT