In a large enough pot, put 2/3 of the milk to boil with the panela in pieces and the cinnamon stick. Make sure the panela dissolves completely.

In another pot, dilute the corn starch in the remaining 1/3 of the milk.

When the heated milk is boiling, add the milk with the cornstarch. Keep moving with a wooden spoon at low heat until the mix gets thick, between 15 to 20 minutes. Moving it constantly will help to avoid the mix the mix burning and getting stuck to the bottom of the pot.

Take of the fire and put the mix on a heat resistant recipient, or in individual cups.

If you cannot find panela (hard to find outside south american markets) you can use a cup of sugar instead, but then the natilla will look white. This does not affect the taste, but if you can find the panela go for it.

If you want, before taking down the mix from the fire you can add shredded coconut or raisins. You can decorate with ground cinnamon.