Take 2 ripe guavas, wash them thoroughly, and chop them into small pieces. Remove the seeds if desired.
In a blender, add 400 grams of chilled plain yogurt (dahi), the chopped guavas, 2 tablespoons of sugar (adjust according to taste), and a pinch of salt.
Blend the mixture until smooth and creamy. If the lassi is too thick, add a little cold water or milk to adjust the consistency.
Pour the guava lassi into serving glasses. Garnish with a few mint leaves or a sprinkle of chaat masala for an extra burst of flavor.
Serve the guava lassi chilled.