Preheat oven to 325°. Cut a piece of wax or parchment paper to fit the bottom of an 8-inch round cake pan. Coat pan with nonstick spray, place prepared paper round in bottom of pan, and spray paper. Sprinkle evenly with ¼ cup almonds.
In a food processor, process remaining 1 ½ cups almonds with ¾ cup confectioners’ sugar until finely ground; set aside.
In the bowl of an electric mixer fitted with the whisk attachment, beat egg whites with salt until soft peaks form. Gradually add remaining 2 tablespoons of confectioners’ sugar and beat until stiff glossy peaks form. Beat in almond extract. In three additions, gently fold in ground almond mixture.
Evenly spread batter into prepared pan, tapping pan on counter to expel large air bubbles.
Bake until golden brown and firm in center, 40 to 45 minutes; cool completely in pan. Invert onto serving plate, and remove wax or parchment paper.