Fill your sink with at least 6 inches of very cold water before starting to cook the spread.
In a large pot over medium-high heat, bring the maple syrup and corn syrup to a boil. Cook the syrup until a candy thermometer reads exactly 232 degrees F/112 degrees C., stirring occasionally. The correct temperature is very crucial in the process.
As soon as the syrup reaches the correct temperature, take the pan off the heat and carefully lower it into the cold water bath. Allow the syrup to rest and cool until it reaches 70 degrees F/20 degrees C, about 30 minutes.
When the syrup reaches 70 degrees F, remove the pot from the cold water bath and beat the cooled syrup with an electric mixer on high speed until the syrup forms a creamy, thick spread, about 3 minutes.
Pack the spread into a container, cover, and ripen in refrigerator for about 2 hours before serving. Maple butter will keep covered in refrigerator up to a month. If chilled maple butter is too hard to spread straight from the refrigerator, allow to come to room temperature.
