1 1/2- 2TBSconrnstarchThis also depends on what you like. The more cornstarch, the thicker your syrup will be. I do 2 TBS.
Instructions
Start by measuring 1/2 cup of warm water in a glass measuring cup. Add in the 3 tsp of yeast, and then sprinkle the 3 tsp of sugar on top. Put a small plate on top of the measuring cup, this helps the yeast to activate. Set aside.
Mix the flour and salt in a large mixing bowl, and then cut in the butter.
Once the yeast mixture has bubbled up, add in one cup of warm water to the mixture. Pour it into your mixing bowl with the flour mixture and stir and knead into a nice smoothe dough. Put a towel over the top of your dough. Get a bowl about half the size of your dough bowl and fill it halfway with water. Put the water in the microwave for about two minutes until it is about boiling. CAREFULLY take it out of the microwave and put the dough bowl over the top of the boiling water bowl. This helps the dough rising to go faster! Allow it to rise for about 30 minutes. While the dough is rising we will make the syrup!
Put 2 cups of water into a saucepan and turn it on high. Add the cinnamon sticks and the piloncillo. You want it to start boiling in order to dissolve the piloncillo completely.
Peel the lemon and set the lemon peel aside. Add the peel to the pan and stir until the piloncillo is completely dissolved. Allow to boil for about 2 minutes while stirring.
You will then mix 1/4 cup of cold water with the cornstarch. Once that is nice and mixed you will add it to the saucepan and stir. This will make your syrup thicken up. Turn it to medium and stir for 3-4 minutes while the syrup thickens up. This part of the recipe really depends on each individual. My mother-in-law likes the syrup a bit more watery than I do, so I add 2 TBS rather than the 1 1/2 TBS she does because we like it a bit thicker. Alter according to your likes 😉  Remove from heat and using a thin strainer you can strain the syrup so you don’t have small bits of the cinnamon stick or the lemon peel in the syrup. Some people skip this step but my little family likes it strained.  Set the syrup aside.
Fill a pot with canola oli for frying. You want to be able to fry up 5-6 at a time, I usually pour in about 3 inches of oil in the pot so that they have room to fry. Turn on the stove to med-high to start the oil heating as you roll out and cut the dough.
Roll out the dough to between 1/4  of an inch to  1/8 inch on a floured surface. My mother in law uses a cup to cut out the Sopaipillas. Using your thumb and pointer finger you rub them together making a small hole in the middle – just like a doughnut! Have all of the Sopaipillas ready to go into the oil.
When the oil is hot, its usually about 5 minutes or so (you can check this by throwing a small piece of dough into the pot to see if it begins to fry or not) you can add in 5 – 6 Sopaipillas to fry. This should just take a minute or two. Halfway through we turn them so they fry evenly. Once they are fried you remove them from the pot and put them in a paper towel lined dish to catch the excess oil. You are ready to eat! Spoon some of the syrup on top of a few of the Sopaipillas and enjoy!