Finely chop the onion and garlic. Remove the skin from the tomatoes and cut into slices of arbitrary shape.
Heat the olive oil in a saucepan and sauté the onion and garlic until soft, 3 to 4 minutes. Add tomatoes and simmer for 5-7 minutes.
Divide the head of cauliflower into sprouts, cut the stem into thin strips. Add to saucepan, season with salt, pepper and coriander. Close the saucepan with a lid and simmer for 15-20 minutes.
Remove the saucepan from the stove, add chopped greens, mix. Serve hot or cool to room temperature.