Preheat a 10" fry pan on medium heat until the rim is hot-to-the-touch. Add the oil and butter and let the butter melt. Swirl the butter into the oil. When the foam from the butter subsides, add the leeks. Saute the leeks until tender and transparent, about 3 minutes.
In a 6-1/2 qt. sauce pot, heat the vegetable broth on medium-high. When broth reaches a gentle boil, add all the ingredients – pasta, leeks, sugar snap peas and broccoli rabe. Continue to heat on a gentle boil for 15-20 minutes.