This is a go-to recipe in the summer months when the produce is at it's peak. The watermelon gives the soup the liquid it needs without making it too heavy and adding just a hint of natural sweetness, which in reality brings out the rest of the flavors. I’ve made gazpacho without it before, and to be honest, if I don’t have any watermelon on hand, I don’t make gazpacho.
As far as the jalapeno goes, I throw the entire thing in, seeds and all. If you don’t want it as spicy, core your jalapeno. Most of the heat is in the seeds and veins. And DO NOT PUT IT ALL IN THE FOOD PROCESSOR AT ONCE. You’ll end up with juice. Chop them in batches so you’ll have better control over the consistency of the recipe. The yogurt and feta add a nice little tang, and help cut the heat if you made it too spicy!
You can adjust any of the above quantities to your tastes. When I make this, I tend to double this recipe because it never goes to waste. —Josh Gannam