My husband makes this delicious pesto - seriously, it's fantastic. He's gotten the recipe fine-tuned to the point that we have ratios of every ingredient to the amount of basil available (he grows his own basil). As I've been learning to code, I thought a great early project would be to build a "pesto calculator," where the user inputs the amount of basil they have, and gets back the perfect recipe for the best pesto ever.
Planned improvements: take units other than grams, be able to toggle what ingredient you want to base the recipe off of (if you want to calculate it based on your amount of cheese, for example), and add info about my favorite uses for pesto and/or where to get great pesto at restaurants.