Line a 9x5-inch (23x12½-cm) loaf pan with parchment paper, leaving some paper overhanging off the sides. Or have silicone maple leaf candy molds standing by. Set aside.

Butter the rim of a medium, high-sided, heavy-bottomed saucepan and attach a candy thermometer.

Pour in the maple syrup and the oil (if using) and bring to a boil.

Let the syrup boil for 5-10 minutes until it reaches the softball stage 235-245°F (112-116°C).

Remove from the heat and do not touch or agitate the syrup. Let cool, undisturbed, until it reaches 200°F (94°C), about 5 minutes.

Remove the thermometer and, with a wooden spoon, begin to stir the syrup. After about 1 minute, you will feel crystals beginning to form at the bottom of the pan, but the syrup will still be fairly clear.

Immediately pour the syrup into the prepared pan or the molds.

If you used a loaf pan, let the syrup cool for a few minutes until it is opaque and firm but still warm. Using the parchment, carefully lift it out of the pan and cut it into squares or pop them carefully out of the molds.

Once completely cooled and hard, transfer to an airtight container for up to 2 weeks.