My mother in-law insists on bringing food to my house.

After 20 yrs, my mother in-law continues to insist on bringing food to our home when we invite her dinner. While the offer is appreciated when I am hosting large family gatherings (hardly ever), her insisting on bringing a ham, a salad and a vegetable to Easter dinner is a bit much. The other side, whenever she hosts a dinner, I am not allowed to bring a cracker. I understand that’s it a power play, but it is becoming incredibly annoying on my end. And to make matters worse, she is a horrible cook and I went to culinary school.