In a heavy-bottomed saucepan over high heat, combine granulated sugar, light corn syrup, and water. Stir constantly as the sugar melts and the mixture starts boiling (meanwhile start beating the egg whites, more on this in step 2), and wait until the temperature reaches 260°F (126°C) which is the hard-ball stage. Remove from heat immediately.
A few minutes before the sugar mixture reaches the desired temperature, beat egg whites in a stand-mixer stiff peaks form. So both the whipped eggs, and the sugar mixture are ready at the same time.
Pour the sugar mixture in the egg whites as the stand-mixer is on high speed, in a steady slow stream until all of the sugar mixture is mixed in with the egg whites.
Add vanilla extract, and scrape the sides of the bowl with a spatula.
Continue beating for 6-8 minutes as the mixture thickens, and starts losing its glossy finish. Make sure NOT to overbeat it (this happened to me as I tested the recipe, and the result wasn't very good!).
To test if the mixture is ready, take a spoon and drop a little bit of the mixture onto parchment paper. If it flattens, then beat for an extra minute and check again.
The mixture must be able to hold its shape, but shouldn't be too thick.
With 2 greased spoons or with a small greased cookie scoop, drop about a tablespoon of mixture onto parchment paper or a silicone mat. If using 2 spoons, then try to create a little curl like soft serve at the top when dropping the candy.
Top with pecans if desired, and allow them to completely dry and harden at room temperature. Depending on the humidity in your kitchen, they might take less or more time to dry (mine usually takes an hour or 2 to set completely).