First, let's prep the matzah balls. In a large bowl, whisk together eggs, oil and seltzer.
Then add matzo meal, baking powder, salt, pepper, paprika and cheese. Mix just until combined. Do not overmix.
The mixture will be sticky, so refrigerate dough for 30 minutes or up to 4 hours so it is not as sticky and you can form the matzah balls!
When you're ready to make the matzah balls bring a large stock pot of salted water or vegetable broth to a boil, and then reduce to a simmer.
Meanwhile, start the soup. In a medium or large stock pot, heat two tablespoons of butter over medium heat. Add onion and a pinch of salt and sauté for 4-5 minutes until soft. Then add the garlic and sauté for one more minute until fragrant.
Add the other two tablespoons of butter and the potato starch and mix until you have a thick paste.
Then add the broth, cream, paprika and cayenne and bring to a boil while stirring. Lower to a simmer and simmer for 15 minutes until thick.
While the soup is simmering, shape the matzo mixture into 12-15 1-inch balls, and place in the simmering water. Cover and cook for 30 minutes. The balls should float and look light! Don't peek!
Back to the soup. Add the broccoli to the soup and simmer just until tender, this will only take a few minutes. Then add the cheese and stir until melted. Season with salt and pepper to taste. Blend slightly with an immersion blender if desired or serve chunky with the matzah balls.