Not an academic. There's not a lot of uniformity from plantation to plantation. Each owner managed their food in a unique way. Some used it as a kind of servile ritual where they would call out names and hand that person their ration for the week and then the slave had to thank them. Others didn't feed them at all, instead they gave them a small plot of land and expected them to grow it themselves. Most owners seemed to practice a combination of the two. They would provide a bag of corn meal and some meat but this was usually barely enough food to survive. The slave would supplement the rest with hunting, their own gardens, barter, etc.

Source: Many Thousands Gone by Ira Berlin. A lot of primary source like Tombee: Portrait of a Cotton Planter, etc.

If you want like actual recipes, they are almost always very simple and basic. Munchies did an article about a guy I keep reading up on who cooks the stuff for tourists in Asheville. There are a couple of colonial/bellum era cookbooks and farm recipes you can Google or find collections of.

Ultimately, you might have better results if you think about what region you want to mimic instead of slaves because their lives were so dramatically different depending on where they lived and what tasks they performed.