Cut the chuck flap tail into bite-sized pieces.
Dice the onion, carrot, and potato into cubes.
Heat olive oil in a pan and sear the chuck flap tail on high heat, just browning the surface, then remove from the pan.
In the same pan, sauté the onion, carrot, and potato.
Add tomato sauce and mix well.
Return the seared chuck flap tail to the pan and pour in water.
Cover with a lid and simmer on medium-low heat for 40 minutes.
Season with salt and pepper, then simmer once more.
Transfer the finished stew to a bowl.