Pour the water into a bowl, and add the cornflour and salt. Stir until a homogeneous mass is formed.
Once mixed, add the butter and knead it with your hands until thoroughly combined, and let it rest.
Dice the onions into small pieces and crush the garlic. Fry the onions and garlic in a frying pan with a little olive oil until it is lightly caramelized.
Add the crushed tomato and a pinch sugar to neutralize the acidity. Let the mixture cook for about 10 minutes over low heat.
Place a frying pan over high heat and add a little olive oil. Season the minced veal with the oregano, salt, and black pepper, to taste. Sauté the minced meat until browned, about two minutes. Remove from the heat.
Make small balls of corn flour dough. Using your finger, make a hole or depression in the center of the ball. Fill with a spoonful of the minced meat and seal the balls, fully enclosing the meat in the dough.
Put a large pot of water on the stove and bring to a boil. Once boiling, add a large pinch of salt, followed by the filled dough balls. Cook until they rise to the surface, then turn off the heat. Let them rest in the water for 30 seconds, then drain in a colander.
Serve the Bollos on a plate or platter and spread with the prepared tomato sauce. Now ¡Buen Provecho!