Chef’s Tip: Store marshmallows between sheets of parchment paper in an airtight container in the refrigerator for up to 1 week. Bring to room temperature 30 minutes before serving.
2 envelopes unflavoured gelatine (4-1/4 tsp.)
3/4 cup cold water
2 cups granulated sugar
2/3 cup corn syrup (light-coloured)
1/3 cup egg whites (refrigerated)
1/4 tsp salt
1 tsp rum extract
1/4 tsp ground nutmeg
2/3 cup powdered sugar
3 tbsp cornstarch
Lightly coat an 8x8x2-inch baking dish with non-stick cooking spray. Line bottom of baking dish with parchment paper. Coat the plastic or paper with nonstick cooking spray.
In a large, heat-proof bowl add up of cold water. Sprinkle gelatine in and set aside.
In heavy saucepan combine remaining up water, 1 cups of the sugar, and the corn syrup. Over medium-high heat bring to a boil. Do not stir. Using a candy thermometer cook until 260 degrees F is attained, approximately 12 to 15 minutes total. Stir mixture carefully into gelatine bowl; mixture will foam up.
In a separate clean large mixing bowl, beat the egg whites and salt with an electric mixer on high speed until foamy. Gradually add remaining up sugar, 1 tablespoon at a time. Add rum extract and nutmeg. Continue beating until stiff peaks start to form. Gradually add gelatine mixture to egg white mixture still beating on high until thick batter forms. Quickly pour marshmallow mixture into parchment lined baking dish, spreading to edges of pan. Lightly coat another piece of parchment paper with nonstick cooking spray and place coated side down, over marshmallow mixture. Let stand at room temperature for 1 to 2 hours until firm.
Combine powdered sugar and cornstarch and sprinkle about a quarter of the mixture evenly onto a large cutting board. Remove parchment cover and carefully invert marshmallow square onto the cutting board. Remove other the side of paper. Sprinkle top with powdered sugar mixture. Using a knife that has been dipped in warm water cut into marshmallows squares. Sprinkle remaining powder on all sides.