Melt the butter in a medium saucepan or Dutch oven over medium heat. Cook till the butter turns brown and stops crackling, about 4 minutes. Add the oil.
Add the onions and sauté until they turn translucent, 3 to 4 minutes. Lower the heat to medium-low, add the garlic, tomato paste, paprika, cumin, and cayenne and cook for 30 seconds till fragrant. Stir in the celery greens, ham, chickpeas, pasta, and water. Add 1/2 tsp of salt, increase the heat to high and bring the water to a boil; reduce the heat to a simmer, and cook covered till the pasta is tender, about 15 minutes. Remove from the heat, taste, and season with salt if needed. If the liquid volume drops after cooking, add more water as needed. Serve the soup warm and garnish with parsley. Leftovers can be stored for up to 4 days in an airtight container in the refrigerator.

Pasta cooking time varies. The smaller the shape, the shorter the cooking time. Adjust your cooking time if you use pasta other than cascatelli, like penne, etc..
The soup volume will reduce after cooking (it also depends on how long you cook due to the pasta size). I added 2 cups/480 ml of water after the cascatelli pasta was cooked to increase the volume.
The butter needs to brown but stop crackling. If you add oil to it early, the water separated from the fat will start to fly out everywhere.
You can sub rotisserie chicken in place of ham.
Cooking time is dependent on the shape and size of your pasta.
Add water to make the soup volume back up after cooking. Again, this will vary depending on the pasta you use.
I’ve not listed the weight for celery greens; it’s a rough 1/4 cup measure. It does not need to be a precise weight here.

Ham and Chickpea Soup