IngredientsNuts & dried fruit
Sauerkirschensour cherries, morellos
Prunus cerasus, a different species from the sweet cherry, Prunus avium. Softer, thinner skinned and much sharper. Almost nobody eats it raw; baked it is the whole point.
The Schattenmorelle is the dark German standard variety. It sits in Black Forest cake, in Kirschmichel and in Rote Grütze. Its acid is what pushes back against cream, sugar and chocolate.
In Mexikoin Mexico
Fresh sour cherries are close to impossible to find here. What the market sells as cereza is the sweet cherry.
What you can get: cerezas en almíbar in the supermarket, frozen cherries, and imported jars of sour cherries through Mercado Libre. The imported jar is the closest thing to the German baking version.
Ersatzwhat to use
Tip the cerezas en almíbar into a sieve and let them drain properly. Throw the sweet syrup away or keep it separately, otherwise that sugar spreads through the whole cake.
Then add lime juice and taste until the cherry is clearly sour again. With frozen fruit, read the label: if it says cereza dulce, treat it the same way.
Vorsichtwatch out
Sweet cherries left uncorrected flatten any cherry cake. The base tastes of sugar and cream only, and the cherry flavour disappears.
Rote Grütze made with sweet cherries turns into jam: thick, sweet, no edge. With lime and less sugar it stays a compote, and the vanilla sauce has something to work against.