Schaum Torte - cooking recipe

Ingredients

10 large egg whites
1/2 tsp. cream of tartar
2 1/2 c. sugar
1 Tbsp. apple cider vinegar
1 tsp. vanilla

Preparation

Do not use fresh eggs.
They must be room temperature.
Beat egg whites with cream of tartar for 15 minutes until very dry. Reduce speed and add sugar, 2 tablespoons at a time until all is used.
Beat an additional 10 minutes.
Reduce speed again to slow and add the vinegar, then the vanilla.
Turn into a large size metal cake pan, ungreased.
Gently smooth the top, do not handle too much.
Put into a 450\u00b0 oven for one minute.
Turn oven off, but leave in the oven overnight or for 8 hours.
Do not open oven door! Do not make on a humid day or egg whites will not hold.
Also be sure utensils and pan are very clean.
Serve with fresh berries or ice cream.