Thanks for all the egg white beating tips. DR Jrand, i used liquid sweetener. So maybe that was the problem?
DR Jose, how would one know if they beat them too long?
Btw, for brussel sprouts, my favorite way is cutting them in little pieces and sprinkling with oil and garlic and then baking them on a cooking sheet for 30 -45 minutes (depending on how brown and crisp you like them).
Liquid sweetener - That's the culprit! If you must use a liquid sweetener, then just fold it in lightly after the egg whites have whipped up. It won't be the same as using granulated sugar, the sweetness may not get all that evenly distributed. And if it did, you'd probably end up deflating the whites with all that extra mixing and stirring. Use sugar.
What are you trying to make? Just a meringue topping for a pie? or some sort of cookie?
You know they're overbeaten when they start to fall apart again. They start to appear dry, curdled looking and water will usually start to pool in the bottom of the bowl.
Here's Emeril's recipe for some meringue cookies. It's basically a meringue with some chocolate chips and nuts mixed in.
2 large egg whites, at room temperature
1/2 teaspoon cream of tartar
2/3 cup superfine granulated sugar
1 teaspoon vanilla extract
1 cup semisweet chocolate chips or finely chopped semisweet chocolate
1 cup finely chopped walnuts
Preheat the oven to 350 degrees F and line 2 baking sheets with parchment paper. Set aside.
In the bowl of an electric mixer, beat egg whites until foamy. Add the cream of tartar and beat until fluffy but not at all dry. (Be careful not to over beat.) Add the sugar gradually, about 3 tablespoons at a time. When 1/2 of the sugar has been added, add the vanilla extract. Continue beating and adding remaining sugar in batches, until all of the sugar is dissolved and the meringue is very shiny and tight. Gently fold in the chocolate chips and chopped nuts. Working one teaspoon at a time, push a teaspoonful of meringue from the tip of 1 teaspoon with the back of another teaspoon onto the lined baking sheets, leaving 1-inch of space between cookies. Place baking sheets in the preheated oven and turn the oven off. Leave the cookies (undisturbed) in the oven for at least 2 hours and up to overnight, or until cookies are crisp and dry.
-And I like roasted brussel sprouts too.