Almost every Indian milk sweet descends from one of two preparations: chhena, made by splitting milk with acid, or khoya, made by driving water off milk with heat. The two behave nothing alike, and that is the root of most kitchen confusion.
The two preparations start from opposite processes
Chhena is separation. An acid added to hot milk destabilizes the casein proteins, which clump and trap fat while the whey, carrying most of the milk sugar, drains away.
Khoya is concentration. Nothing is removed and nothing is drained. Water leaves as steam, and everything else in the milk, including all of the lactose, stays in the pan and gets denser.
So one product has had its sugars washed out and the other has had them concentrated. That single difference drives how each responds to sweetening, shaping and heat later on.
Chhena is elastic because its protein is still loose
Freshly drained chhena has protein curds that have not been cooked hard. Kneaded, they smear into a continuous mass that can stretch a little without tearing.
That elasticity is what allows a ball of chhena to swell in simmering syrup rather than dissolve or crack. The protein network expands as liquid moves in and holds the new shape.
Overheat the same chhena and the proteins tighten irreversibly. The mass turns grainy and rubbery, and no amount of kneading brings the softness back.
Khoya is crumbly because its sugars have crystallized
In khoya the lactose concentrates as water leaves, and depending on how fast it is cooked it either stays smooth or forms visible grains. Cooks name the grades by that texture.
A khoya cooked gently and stirred constantly stays soft and pliable. Pushed hotter and longer, it dries into a firm cake that grates rather than spreads.
This is why khoya-based sweets fracture cleanly and chhena-based ones squash. The structure holding them together is crystallized sugar and browned protein rather than a hydrated protein web.
Sourcing the two is not equally easy in an American kitchen
Chhena needs only whole milk and lemon juice or vinegar, both of which any US supermarket carries, so it is the more practical of the two to make at home.
Khoya needs a long stretch at the stove with a heavy pan and steady attention, which is why Indian groceries sell it frozen and why home cooks often reach for milk powder instead.
Recipes rarely say which family a sweet belongs to
A recipe that calls for kneading until smooth and then boiling in syrup is a chhena recipe, whatever it is named. One that calls for cooking until the mass leaves the pan is khoya.
Reading a recipe that way tells you in advance what can go wrong. Chhena fails by toughening, khoya fails by scorching, and the two fixes have nothing in common.