Heat a little oil in a skillet. Add the chopped onion and celery, sauté, then add the ground beef. Season with bouillon powder or salt and pepper, and cook until the meat is browned.

In a saucepan or skillet, heat a little oil and sauté the tomato puree. Season with bouillon powder or salt, pepper, and add some herbs like basil, oregano, thyme, and garlic. Add this sauce to the meat mixture.

In a saucepan, melt the butter with a splash of oil. Add 3 tablespoons of flour and stir until it starts to turn golden. Gradually add the milk, stirring until you get a smooth, thick consistency. Season with salt or bouillon powder, pepper, and nutmeg.