Preheat oven to 325 degrees F (165 degrees C). Line 2 baking sheets with waxed paper.
Beat egg whites in a bowl with an electric mixer until fluffy. Add sugar gradually, continuing to beat on high until firm peaks form. Fold in ground almonds gently until incorporated into the dough. Drop tablespoonfuls of dough 2 inches apart onto baking sheets. Sprinkle slivered almonds onto tops.
Bake in the preheated oven until golden, 12 to 15 minutes.
This is such an easy recipe and always goes down extremely well to pretty much every audience. To mix it up a bit you can put a teaspoon of flavoring in with the sugar; peppermint works extremely well, as do lemon and almond. Try drizzling some melted chocolate over the top or just leave plain. Also works well as a pudding stacked with layers of whipped cream and raspberries!
If you want to garnish with flaked almonds, allow dough to set for 15 minutes prior to placing the almonds on top; this will prevent the almonds from sinking. When making for the kids, I skip this step as it makes it much quicker.
Parchment can be used for easier cleanup/removal from the pan.