Heat a large soup pot, add olive oil and butter. Add onions, slat, pepper, seasonings and smoked paprika, stir well to coat. cook until onions are soft and translucent, about 5-6 mins. Stir in garlic and tomato paste, using the back of the spoon to mash evenly. Cook for another 5-6 mins, allowing the tomato paste to become golden in spots. Add both cans of the tomatoes with juice and the broth, bring to a boil. Reduce to a simmer and let bubble for 1 hour, stirring occasionally. Using an immersion blender, blend until smooth. You can add 1/3 cup mascarpone cheese and 1/3 cup grated havarti cheese.