There should be on a cooking recipe that tells you if you have already learn that recipe.
So when you are in the guild store or your inventory you know if you have the recipe already learned.
Recipes of the same item should stack instead of taking up one bag slot each. Sometimes after a good supply run my junk section has 30+ recipes, but only 5 or 6 unique recipes.
"But you know the old saying: When life gives you lemons...
Go murder a clown."
―Festus Krex