Place beans, seasonings, tahini, and lemon juice in blender. (A heavy-duty blender works best for this recipe; other blenders may not get the mixture smooth enough.) Set aside.
Cook pasta according to package directions. Reserve 1 1/4 cups of pasta water when draining pasta. (The pasta water will be added to the blender.)
While pasta is cooking, sauté onions in oil over medium heat for 2 minutes. Add spinach, cover pan, and cook over medium heat until spinach is tender (about 4 minutes), stirring occasionally.
Add minced garlic and cook for 1 minute. Remove from heat and set aside.
When pasta is done, drain pasta reserving 1 1/4 cups of pasta water. Add pasta water to ingredients in blender and blend well until mixture is smooth. This may take several minutes if you don’t have a heavy-duty blender.
Season to taste.
Stir blender mixture into spinach mixture. Heat over low heat until hot. Serve over pasta.
Recipe by JennifersKitchen at https://jenniferskitchen.com/2016/05/creamy-cannellini-spinach-pasta.html