Feeling annoyed with my mother

So my mother is such a caring person, she is always willing to help us no matter what is it. If we needed help when my lb was still a newborn she would be over in a flash and stay all night. However she loves to give us unsolicited advice. My husband and I both decided when we started solids that we wanted to keep it to fruits and vegetables only for the start. However she kept pushing us to give him rice cereal and we ended up having an argument about. Than she tried to push a specific brand of babies rusks onto him which are loaded with sugar. He is only 5 months and I am not comfortable giving him foods loaded with sugar. I expressed how we felt about this, however now she tells me she has gone and bought him these rusks for Christmas! My husband is fuming and ready to start a fight. I know it may seem silly however he is our child and it is 100% our decision on how to raise him. Am I being unreasonable here? I just don't know how to handle this without causing huge arguments.