I have been trying for some time to make a meringue cake layer (like for Pavlova, but flatter, thinner) and I have not had any luck.
The recipe I use is 50 grams of sugar per one medium egg white, and 1/4 or 1/2 teaspoon of cream of tartar if using 3 egg whites.
So I use 150 grams of sugar, 3 medium egg whites, and 1/4 teaspoon of cream of tartar. (I stopped adding flavourings because I think they might contribute to my failure.)
I use glass or metal bowl that has been washed, dried, and lightly wiped down with a lemon sliced in half. The mixer beaters are also washed and wiped with lemon juice. The egg whites are at room temperature when I start mixing.
How I make it - I use a hand-held electric mixer and beat the egg whites (oh high speed) until somewhat stiff peaks form, and then I start adding in the sugar, a spoonful at a time, beating well between each addition (15-20 seconds on high speed) until it becomes almost shiny.
I draw four circles on the baking paper (15 cm in diametre), divide and spread out the egg whites with a spoon, and put it immediately in the oven at 100C (212F), for 60 minutes, then I turn off the oven, leave them in for 15 minutes more, and take out.
I have tried baking (drying, essentially) them at 90C, at 120C, all with varying results, but they almost always come out cracked and not white.
I know I am doing something wrong, but I do not know what... If anyone can help, I will be greatly thankful.