Butter two 8-inch round cake pans, and line bottom with buttered parchment or wax paper.

Position a rack in the middle of the oven and preheat to 350 degrees.

Combine the flour, baking powder, and salt in a bowl, mixing well.

Place the butter and sugar in the bowl of a heavy-duty mixer fitted with the paddle attachment and beat on medium speed for about 5 minutes, or until very soft and light. Beat in the vanilla.

In a medium bowl whisk together the egg whites. Add milk and mix until combined. Add to butter mixture and whisk for 2 minutes until light and fluffy.

Reduce the mixer speed to low and beat in one-third of the flour mixture, then one-third of the milk mixture, stopping and scraping down the bowl and beater after each addition. Beat in another third of the flour, then another third of the milk mixture. Scrape again. Repeat with another remaining flour and the remaining milk mixture.

Pour the batter into the prepared pans and smooth the tops.

Bake the layers for about 25 to 30 minutes, until they have risen and firm and a toothpick inserted in the center emerges clean. Cool the layers in the pans on racks for 5 minutes, then unmold onto racks to finish cooling right side up.

Swiss Meringue Buttercream Icing

Makes 5 cups of buttercream

5 large, fresh egg whites (150 g), room temperature

1 ¼ cups sugar (250 g) sugar

½ teaspoon salt

1 1/2 cups (340 g) unsalted butter, room temperature, cut into cubes

3 teaspoons vanilla

Add egg whites and sugar to an electric mixer bowl, and place over a pot of simmering water (not boiling), without the bottom of the bowl touching the water. Whisk constantly but gently, until temperature reaches 160°F, or if you don't have a candy thermometer, until the sugar has completely dissolved and the egg whites are hot. Remove bowl and place on mixer stand.

With whisk attachment of mixer, begin to whip until the meringue is thick, glossy, and the bottom of the bowl feels neutral to the touch (this can take up to 10 minutes or so). Don't begin adding butter until the bottom of the bowl feels neutral, and not warm.

Switch over to paddle attachment and with the mixer on low speed, add salt and mix. Add butter cubes, one at a time until incorporated, and mix until it has reached a silky smooth texture (if mixture curdles, keep mixing and it will come back to smooth). If mixture is too runny at this point, refrigerate for about 15 minutes and continue mixing with paddle attachment until it comes together. Add vanilla and continue to beat on low speed until well combined.

Notes:

Keep in airtight container in refrigerator for up to one week, leaving out at room temperature when needed, rewhipping in mixer for 5 minutes.

You can freeze buttercream for up to 6-8 weeks. To thaw, place on counter overnight, and rewhip for 5 minutes with paddle attachment in an electric mixer.

If buttercream still doesn't have its satiny finish after rewhipping, microwave 1/3 of the buttercream for approximately 10 seconds and add to remaining buttercream in mixer bowl, beating for a few moments to incorporate.

To Frost the Cake

After the cake has completely cooled, take a serrated knife and cut away the crisp edges of the cake and brush off any crumbs. Place on serving platter. Take 4-5 sheets of waxed paper or parchment and place under and around cake to protect platter from buttercream.

To the bottom layer - take 1/2 - 3/4 cup of any kind of jam you prefer and spread it almost to the edges of the cake leaving a 3/4-inch boarder (to help prevent the jam from leaking through the buttercream). Take 1/4 of the buttercream and gently frost the bottom layer right to the edges. Take remaining cake and place on top and lightly frost entire cake with a light coating of buttercream (called a crumb coating). Refrigerate for 20 minutes and continue to frost the entire cake. If you want to make decorations, reserve some of the buttercream. You can also make a quick powdered sugar buttercream to decorate the cake and add food coloring if you prefer a cake with lots of Swiss Meringue buttercream. Frost the cake and decorate however you would like.