Generously season beef cubes with salt and pepper; set aside.
In a Dutch oven over medium-high heat, add 2 tablespoons oil.
When hot, working in batches, add well-seasoned beef cubes and sauté until no longer pink, about 1:30 minutes.
Scoop them into a bowl using a slotted spoon and set them aside while working with the remaining cubes. If the next batch needs oil, add more.
When the meat is done, add ghee, reduce the heat to medium, add yellow onions and sprinkle on salt; sauté for 1 minute, scraping the bottom of the pot to dislodge any brown bits.
Add red peppers and green peppers; cook for 3 minutes.
Add ginger and garlic; sauté for 1 minute.
Add madras curry paste and tomato paste; stir well to coat.
Return the meat including any accumulated juices, add coconut milk, beef broth, brown sugar and diced tomatoes; stir well.
Bring the mixture to a boil, cover, reduce the heat to medium-low and let it simmer gently for 1 ½ hours, stirring occasionally.
When time is up, add cornstarch mixture and stir until the curry thickens, about 45 to 60 seconds
Serve with rice, naan bread and garnish with chopped cilantro, sliced Fresno chiles and lime wedges.