Pasta water is a versatile ingredient that can be used in many ways. Here are some of the most common uses for leftover pasta water:

1. Sauces: After your pasta is done cooking, scoop some leftover pasta water into your sauce. The starch in the pasta water acts as a thickener and pulls the sauce together, giving it a smooth texture and richer flavor.

2. Soup base: Pasta water makes an excellent base for a hearty soup or broth. Use it to steam your veggies, then add that well-flavored pasta water to some stock, leave it to cook, and season to taste – a remarkable soup/broth base awaits.

3. Bread and pizza dough: According to Nigella Lawson, pasta waters starches can actually help home-baked bread to rise. Just use the pasta water in place of tap water.

4. Watering plants: Let the leftover pasta water cool down and use it to water your plants. It provides plants with minerals and can be used as an NPK fertilizer, which stands for nitrogen, phosphorus, and potassium. The starchy water also promotes beneficial bacterial growth, which in turn can help you to grow healthier plants.

5. Detergent: Believe it or not, the starch in pasta water can also be used as a natural detergent.

6. Thinning out condiments: Pasta water can be used to thin out condiments like pesto and sauces that have coagulated in your fridge. It wont dilute the sauces flavor and will give it a silky texture.

7. Softening legumes: The starch in pasta water can help soften legumes like chickpeas and beans.

8. Cooking other pasta: You can use leftover pasta water to boil future pasta.

9. Making a broth: You can use leftover pasta water to make a vegetarian broth for soup.

10. Promoting plant growth: The starchy water from pasta can be used to promote beneficial bacterial growth in plants, which in turn can help you to grow healthier plants.

In summary, leftover pasta water can be used in many ways, from thickening sauces to watering plants. Its a versatile ingredient that can add flavor and texture to your dishes while reducing waste.