In small bowl, whisk 1 1/2 cups sugar with cornstarch; set aside. Place egg whites in a clean, dry, bowl of standing mixer fitted with whip attachment. Beat on medium speed until frothy. Add cream of tartar and salt. Increase speed to medium high and beat to soft peak.
With mixer running, slowly add sugar/cornstarch mixture. Continue to beat to stiff peak, 3 to 5 minutes. Reduce speed to low and add vanilla. Remove bowl from mixer and fold in ground almonds with rubber spatula.
Divide the meringue between the pans and smooth the tops. Sprinkle sliced almonds on top. Bake until the color of the meringues is light beige and the top feels crisp, but the center is still soft, 50 to 60 minutes. Transfer pans to wire rack to cool completely.
While meringues are cooling, toss strawberries with 1 tablespoon sugar. Using mixer fitted with whip attachment, whip cream with remaining tablespoon sugar and remaining teaspoon vanilla on medium speed to soft peak. Keep chilled until ready to assemble.
Run knife along inside edge of pans and carefully invert meringues onto plates. Place one meringue on serving plate, top side up. Spread half of strawberries with juice onto meringue and top with half of the whipped cream.
Place second meringue on top, top with cream, and then strawberries. Dust with confectioners’ sugar and serve immediately.
