Skip this section if you have homemade paneer or store bought ricotta. Your homemade paneer/chenna has to be moist and unset with some amount of whey in it.
Pour 6 cups of full fat milk to a pot and bring it to a boil. Add 2 tablespoon lemon juice or half cup yogurt to the hot milk.
Stir and continue to boil till the milk begins to curdle. Turn off when you see the whole pot of milk curdled well & whey has separated completely.
Pour 2 cups cold water immediately. Drain this to a cheese cloth lined over a colander. Hold the cheese cloth carefully under running water and rinse it well to remove the lemon flavor.
Bring the edges together and squeeze off to drain all the excess whey from the cheese. Hang it for about 10 to 20 mins.
Grease a small tray and line with parchment paper. Keep this aside.
Pour condensed milk to a heavy bottom non-stick pan. Add the paneer or ricotta cheese. Mix them well and begin to cook on a medium flame stirring continuously.
The mixture thins down initially and then slowly begins to thicken. Continue to stir and cook until the mixture begins to thicken.
Then reduce the flame to low and continue to cook stirring until it becomes thick. It took about 8 to 9 mins for me. If you are using store bought ricotta it will take longer. (Check the video or step by step photos)
Do not overcook. The mixture has to be moist and juicy but not dry.
When you see the mixture begins to leave the sides yet remains juicy (not runny) transfer the kalakand immediately to the greased tray.
Spread it to ½ to ¾ inch thickness. Sprinkle nuts and gently level with a spatula.
Refrigerate kalakand for at least 2 hours. It will set to a soft set crumbly cake. Then cut to desired sizes. I cut mine to 12 (¾ inch thickness) or to 16 (½ inch thickness)
Remove it from the fridge 30 to 60 mins before serving. Kalakand is best served warm or chilled but the texture won't be good if it is too cold.