The single longest step in most Indian dairy sweets is reducing milk. Doing that once in advance changes what is realistically possible on an ordinary weeknight.
One preparation feeds many recipes
Reduced milk solids are a shared base rather than a component of one dish, appearing in cut sweets, fillings, rolled sweets and enriched puddings alike.
A cook holding a container of it can produce several different sweets from it, each finished in a fraction of the total time.
That converts sweet-making from a project into an ordinary task, which is the difference between making these things occasionally and making them regularly.
Batch reduction is more efficient than repeated reduction
Reduction is limited by evaporation, and a wide pan running for an afternoon uses the same attention as a small pan running for an hour.
Doing it once at a larger scale therefore costs proportionally less time and much less standing at the stove than doing it four separate times.
It also produces a more consistent result, since a single batch has one browning history and one texture rather than four slightly different ones.
The stopping point should suit the intended uses
Stopping while the solids are still soft gives a versatile base that can be cooked further for any individual recipe.
Taking it to a firm, dry stage commits it to sweets that want that texture, and it cannot easily be brought back to a softer state.
Most cooks holding a standing batch stop soft for that reason, since the remaining cooking is short and can be done per recipe.
Storage decides how long the head start lasts
The solids are a dairy product with moisture in them, so they are cooled promptly, packed airtight and refrigerated rather than left out.
Portioning into small containers before chilling means only what is needed comes out, and the rest is never warmed and re-chilled.
Because holding times for prepared dairy depend on handling and temperature, published food safety guidance is the appropriate reference rather than an estimate.
The same logic applies to the other slow components
Syrup, roasted flour, ground nut powders and clarified ghee are all stable, all slow to make and all shared across many recipes.
A kitchen holding those four alongside a container of milk solids can produce most of the common sweet repertoire without any long preparation stage.
Which is precisely how professional sweet kitchens organize themselves, and the reason a shop can turn out a dozen items from what looks like a small operation.