In a large pot, heat 2 tablespoons of olive oil over medium heat until shimmering. Add your sliced beef sirloin in batches, browning for about 4-5 minutes until it's well-browned and no longer pink. Use a slotted spoon to remove the beef from the pot and set it aside on a plate, keeping the flavorful drippings in the pot.

With the same pot still over medium heat, add 1 chopped onion and 1 diced green bell pepper. Sauté the vegetables for 4-5 minutes until they are tender and translucent, stirring frequently to prevent sticking. Add 3 minced garlic cloves for the last minute of cooking, until fragrant.

Return the browned beef to the pot with the sautéed vegetables. Pour in 4 cups of beef broth, stirring to combine all the ingredients nicely. Bring the mixture to a boil, then reduce the heat to low and let it simmer for about 15 minutes.

After simmering, stir in 1 cup of heavy cream and 2 cups of shredded provolone cheese. Keep the heat on low to gently melt the cheese, stirring occasionally.

Taste your soup and season with salt and freshly cracked black pepper to your liking. Serve hot, garnished with fresh parsley or chives if desired.