Grease a 9x13 baking pan, sprinkle with powdered sugar until well coated, set aside.

In the bowl of a stand mixer add ½ cup cold, flat beer. Sprinkle with gelatin. Allow to stand while the sugar is being prepared.

In a large saucepan (mixture will bubble up) over medium heat, add the water, 2 cups sugar and corn syrup. Stir until the sugar has dissolved.

Raise heat to high and allow to boil until the mixture reads 240F on a candy thermometer (about 6-8 minutes).

Once the temperature has been reached, turn off heat.

Turn the mixer on low and slowly pour the hot sugar mixture into the gelatin. Once all the sugar has been added turn the mixer on high until light and fluffy and tripled in volume, this can take up to 10 minutes.

While the mixer is running, prepare the egg whites. Add the egg whites to a bowl with the salt. Beat on high with a hand mixer until stiff peaks form. Sprinkle with remaining 2 tablespoons sugar, beat until stiff peaks return.

Gently fold the egg whites and vanilla extract into the stand mixer ingredients until just combined.

Pour the marshmallows into the prepared pan. Sprinkle with powdered sugar. Allow to set at room temperature until set, about 2 hours. Remove from pan, cut into squares. Toss with additional powdered sugar to prevent from sticking together.