Cut the carrots into suitably thick slices, ideally in the shape of flowers. Cut the onion into wedges. Quarter the tomatoes and dice them into cubes.
Use a mini chopper to mince garlic and shallots separately. Cut the lemongrass stalks into short baton-like shapes. Slice some of them finely to mince with the chopper.
Cut the beef into bite-sized cubes. Soak them in a mixture of minced aromatics (lemongrass, garlic, shallots), five-spice powder, turmeric powder, ginger powder, cashew powder, black pepper, chili powder, Vietnamese fish sauce, brown sugar, and oyster sauce. Mix vigorously and marinate for 20 - 30 minutes.
Sear the marinated beef cubes on all sides for a few minutes in the mini stock pot. Set aside.
Saute minced shallots and garlic in olive oil, then add tomato cubes to the pot. Stir-fry until they turn soft.
Add minced garlic and lemongrass batons, then cook until fragrant.
Return the beef to the pot and give a good stir. Add star anise, cinnamon sticks, and bay leaves to the pot. Cook for 2 minutes.
Pour coconut water into the pot and turn down the heat. Season with salt and brown sugar, then stew for 1 hour 15 minutes.
Then, add carrot slices and cook for another 15 minutes.
Remove star anise, bay leaves, cinnamon sticks, and lemongrass batons from the pot.
Turn up the heat and add onion wedges.
To thicken the stew, mix cornstarch with a little water, then stir the mixture with it.
Garnish with Thai basil, scallions, and onion slices/ rings on top. Serve with fresh herbs and baguettes.