They can claim anything they want. But they can't copyright a recipe. They can only copyright unique creative material such as a description. Directions and ingredients are not unique so they can't own a recipe and anyone can modify said recipe because it isn't owned. Lord knows we had been thru that time and time again on another recipe site now sold to the mass market "I can't cook but I can own a site" world. "That's MY RECIPE TAKE IT DOWN." Oh do shut up and read the copyright laws. However once modified, it ain't theirs and the person modifying needs to say it ain't. That done? Just tell them to shut up then go ahead and post the new recipe.
Since this came up when I was looking for Southern Vegetarian Recipes in case anyone else finds this looking for the recipes you might want to get the cookbook
I would go straight for a good rich Egg Custard Pie and also some French Silk Chocolate Pie. The version of French Silk I use comes from the NYT Heirloom
1 cup butter
1. Beat the butter with the sugar until very well blended. Mixture should be smooth, fluffy and pale yellow.
2.Blend in the chocolate and the vanilla.
3. Using an electric mixer at medium speed, beat in the eggs, one at a time, taking 5 minutes to incorporate each.
4.Turn the mixture into a pie shell and chill several hours. Decorate with whipped cream.
Note this is very rich.