Spray a 9x13 baking dish with nonstick cooking spray and line the dish with a sheet of parchment paper, letting it hang over the sides of the dish for easy removal.
Add the butter and sugar to a large, heavy-bottomed saucepan and cook over medium-high heat. Stir constantly, for about 5 minutes, until the butter is melted.
When the butter has completely melted, bring the sugar mixture to a boil. Allow the toffee mixture to boil until a candy thermometer reaches 285 degrees F. Be patient, as this process may take up to 30 minutes.
Remove the pan from the heat and stir in the vanilla extract. Pour mixture into the prepared baking dish, making sure to scrape the sides of the pan to get all of the mixture out.
Allow the candy mixture to sit for 2-3 minutes, then sprinkle the white chocolate over the top. Cover with nonstick aluminum foil for 5 minutes, then remove and use a spatula to spread the white melted chocolate chips over the toffee in a thin, even layer.
Combine the remaining ½ cup of sugar and 1 Tablespoon of cinnamon then sprinkle over the top of the white chocolate.
Place toffee in the refrigerator until set, about 1-2 hours.
Use the parchment paper to lift the hardened toffee out of the baking dish. Break into bite-sized pieces and serve or store in an airtight container.