Before you start, check the boiling point of water as it can vary depending on altitude. If it boils at 212 degrees, then follow as is! If it boils at a higher - or lower - temperature then add or subtract the temperature difference to or from 235 degrees accordingly.
Pour the maple syrup into a saucepan with high sides (the syrup will bubble and rise up as it boils, so the high sides are essential). clip a candy thermometer to the pan so that it’s submerged but not touching the bottom.
Line the inside rim of the pan with the butter (this will help stop the syrup from bubbling over).
Heat the syrup to 235 degrees. if it looks like it will bubble over, add a small piece of butter to the pan.
Once it reaches 235 degrees, remove it from the heat and leave the syrup undisturbed until it cools to 190 degrees.
Once it reaches 190 degrees, remove the thermometer and begin stirring the syrup slowly with a wooden spoon. After a few minutes, you’ll notice that the syrup will lose its glossy finish and will start to thicken and crystallize at the bottom.
Continue to stir until you can see crystallization through the syrup and as soon as it turns a light, creamy color, pour immediately into your mold! The syrup can go from liquid form to hard candy in a matter of seconds.
Let the candy cool in the molds for around an hour or until the centers have firmed; then gently remove them from the molds.