Starting with the stew, bring a large saucepan or Dutch oven to a medium-high heat. Add the oil and butter, once melted, add the beef and sauté until browned.
Add the onion, celery, red bell pepper, and carrots. Sauté for 3 minutes or until the vegetables edges start to brown.
Add the tomato paste, garlic, chili, and thyme. Sauté for another 3 minutes or until the tomato paste starts to darken in colour. Note: be careful to not burn the garlic.
Add the warm beef stock, vinegar and soy sauce. Stir and cover with a tight fitting lid. Allow to simmer on a low-medium heat, stirring occasionally. Cook for 1 hour or until the beef is tender. Top up with any additional beef stock if needed. Note: the stew must simmer and not boil otherwise there's a high chance of the stew burning.
Meanwhile, prepare the creamy samp.