Begin by blanching your broccoli and placing in a ice bath, reserving the broccoli water. Set aside.
In a pot or Dutch oven over medium-high heat, add your olive oil. Once glistening, add your leeks and broccoli. Seasoning with salt and pepper. Then add in your basil and spinach. Wilt everything down for 5 minutes.
Add in your reserved broccoli water to let everything combine. Blend until smooth, and serve!