Makes about 30 pieces
2 cups pure maple syrup
¼ cup granulated sugar
¼ cup light corn syrup
¼ tsp. sea salt
2 large egg whites
1 cup chopped black walnuts
Line a large tray with parchment paper or wax paper.
Place the maple syrup, sugar, corn syrup, and salt in a deep pan and stir to dissolve the sugar. Place the pan over medium heat and bring to a boil. Boil until the syrup reaches hard-ball stage, 250-260°F on a candy thermometer—so called because the syrup should form a hard ball when a small amount is dripped from a spoon into a glass of cold water. Maple syrup scorches easily, so be careful not to heat it past 260°F.
When the syrup is close to reaching the right temperature, beat the egg whites in the bowl of a stand mixer, using the whisk attachment on medium-low speed, until stiff peaks form. (Alternately, you can beat the whites by hand, but I recommend a mixer.)
When the syrup has reached hard-ball stage, turn the mixer up to medium speed. Very carefully pour a slow, thin stream of syrup into the egg whites while beating. When all the syrup is in the bowl, raise the mixer’s speed to medium-high and beat for another five minutes, or until the divinity begins to make ribbons that stretch from the sides of the bowl. When it is ready, it will look dull, almost like caulk.
Stir in the black walnuts. Working quickly, use two spoons to drop tablespoon-sized pieces onto the prepared tray. Don’t let them touch. They will dry as they cool. When ready, they should have an almost crisp outer shell with an interior that is slightly stretchy but melts easily on the tongue. You can store them in an airtight container at room temperature for up to a month.
Note: If you can’t find or forage black walnuts locally, you can order them from Hammons Black Walnuts, a Missouri company that has been selling them for decades.