Add whole milk and condensed milk in a thick bottomed saucepan or kadai. Stir and mix with a wired whisk so that the condensed milk is mixed evenly with milk.
If you do not prefer a sweeter basundi add ¼ cup milk or more according to your preferences. Keep in mind the mixture thickens while cooking, so add the milk accordingly.
Place the pan on stovetop. Keep heat to a low. Bring this mixture to a gentle boil. Keep on stirring at intervals so that the liquids do not get browned or burn from bottom.
Cook on low heat and simmer for 20 to 25 minutes. Stir after intervals of 3 to 4 minutes.
Gradually the basundi mixture would begin to thicken.
Scrape the milk solids from the sides and the cream collected on the top and add it back to the basundi mixture.
Add grated nutmeg or nutmeg powder, slivered nuts, cardamom powder and saffron strands.
Mix and stir to combine. Continue to simmer for 1 to 2 minutes more.
Pour in serving bowls. Serve basundi hot or warm or cold. While serving garnish with some slivered nuts like almonds or pistachios. You can serve as is or with poori.
Sweetness is relative. With 2 cups milk, the basundi is slightly sweet for my taste, but my family found it perfect. So when the basundi is cooked, check the taste. And if you find it more sweet, add in about ¼ cup to ⅓ cup warm or hot milk to lighten the sweeter taste. You can choose to add more milk when you mix it with condensed milk or after the cooking is complete.
Stir the mixture often while cooking so that the liquids do not burn or get brown at the bottom of the pan.
I would recommend to add both chironji and nutmeg to get the authentic flavors if you have time. Chironji gives a nice crunch and makes this dessert more flavorful.
Do use whole milk for a creamy consistency. Toned milk or low-fat milk won't give you the same results.
For chironji take care as it gets quickly rancid and tastes slightly bitter. If the chironji has become rancid, then do not add it.
You can skip adding saffron but do add cardamom powder.
Feel free to add the nuts that are easily available to you. Some options are: pine nuts, cashews, pistachios, almonds.
For parties or get togethers you can easily scale this recipe depending upon the servings you want.