Place egg whites in a large bowl; let stand at room temperature 30 minutes. Preheat oven to 325°. Line bottoms of two greased 8-in. round baking pans with parchment paper; grease paper.
In a large bowl, cream butter and sugar until light and fluffy. Add egg yolks, one at a time, beating well after each addition. Beat in extract.
In another bowl, whisk flour, baking powder and salt; add to creamed mixture alternately with milk, beating well after each addition. Transfer to prepared pans.
For meringue, with clean beaters, beat egg whites with vanilla and cream of tartar on medium speed until foamy. Gradually add sugar, 1 tablespoon at a time, beating on high after each addition until sugar is dissolved. Continue beating until stiff glossy peaks form. Spread over batter in pans; sprinkle with almonds.
Bake 28-32 minutes or until meringue is lightly browned. Cool completely in pans on wire racks (meringue will crack).
Meanwhile, for filling, in a small heavy saucepan, mix sugar and cornstarch. Whisk in milk. Cook and stir over medium heat until thickened and bubbly. Reduce heat to low; cook and stir 2 minutes longer. Remove from heat.
In a small bowl, whisk a small amount of hot mixture into egg yolks; return all to pan, whisking constantly. Bring to a gentle boil; cook and stir 2 minutes. Remove from heat; stir in butter and vanilla. Cool completely.
Loosen edges of cakes from pans with a knife. Using two large spatulas, carefully remove one cake to a serving plate, meringue side up. Gently spread with filling. Arrange strawberries over filling. Top with remaining cake layer, meringue side up. If desired, serve with whipped cream. Refrigerate leftovers.