I feel like this is something so simple but I can't find anything that does this. I want an application/website/program that allows me to select my recipes for the week or month and then creates a grocery list from those recipes.

I have found tons of sites that creates a shopping list for you, but it also pre-selects your recipes and doesn't let you edit them. I want the functionality to swap a meal for another meal and have it update my shopping list.

Does anyone know of any website or app that does this?? I am hoping to try Paleo if I could find a good list generator.