Nutrition per serving may change if servings are adjusted.
2 large egg whites
1/4 teaspoon cream of tartar
1/4 teaspoon salt
1 cup sugar
3/4 cup blanched slivered almonds, toasted and coarsely chopped (see Tip)
Preheat oven to 250 °F. Line 2 baking sheets with parchment paper or brush them with oil and dust with flour, shaking off excess.
Beat egg whites in a large mixing bowl with electric mixer until foamy. Add cream of tartar and salt; beat until soft peaks form. Gradually add sugar, beating until stiff but not dry peaks form. Fold in almonds.
Drop the batter by heaping tablespoons onto the prepared baking sheets. Bake until light golden and firm to the touch, about 1 1/2 hours. Reverse pans halfway through to ensure even baking. Transfer cookies to a rack and let cool.
Make Ahead Tip: Store in an airtight container for up to 1 week.
Tip: To toast slivered almonds: Place in a small dry skillet and cook over medium-low heat, stirring constantly, until fragrant and lightly browned, 2 to 4 minutes.