Add 2 1/4 cups pure maple syrup to a medium-sized saucepan over medium heat and allow it to reach a boil. Turn the heat down to medium-low heat and allow it to simmer for 5 minutes.
Add 1 cup of heavy cream to the boiling maple syrup mixture and stir until combined. Turn the heat back up to medium and place a candy thermometer inside the candy mixture.
Cook until the candy reaches 234 degrees. While candy boils it can double in size, keep an eye on it and if the mixture is about to boil over, turn the heat down a bit and stir until it calms back down.
Once the candy reaches 234 degrees, remove from the heat and add 3 tbsp of unsalted butter. Stir with a wooden spoon until the butter is fully melted.
With the wooden spoon, whip the fudge mixture for 3-5 minutes so that it can cool down and thicken.
Pour into a greased pan; I like to use the Candy Pan or an 8x8 baking dish.
Allow the candy to set for about 1 hour. Slice and enjoy!