Step 1

Preheat oven to 350°F, and grease 2 8-inch diameter cake pans.

Step 2

In the bowl of a stand mixer outfitted with the paddle attachment, or in a large bowl if using electric beaters, beat the butter and sugar together at medium speed until light and fluffy -- about 4 minutes. Beat in the vanilla extract. Beat in the eggs one at a time, stopping to scrape down the bowl as necessary. At low speed, beat in the flour just until it disappears into the batter. Do not overmix.

Step 3

Divide the batter among the prepared cake pans. Bake until the cakes pull away from the walls of the pans, and the tops color lightly -- 22-26 minutes. Let the cakes cool in their pans for 5 minutes. Then place a tea-towel over one cake, and invert to unmold. Place the cake on a cooling rack. Repeat for the other cake. Cool completely.

Step 4

Making the buttercream -- In the bowl of a standing mixer outfitted with the whisk attachment, or in a large bowl if using a manual whisk or electric beaters, whisk together the butter and half of the confectioners' sugar until smooth. Then whisk in the remaining confectioners' sugar. If the mixture is too thick to pipe or spread, whisk in 1 tablespoon of the milk or cream. Add droplets more of the milk or cream in order to achieve the proper spreading/piping consistency.

Step 5

Determine which cake has the prettiest top, and place the other, less-attractively-topped cake upside down on a plate or cake stand, and spread it with the strawberry jam. Pipe or spread the buttercream over the jam. Then place the second cake top-side-up on the filling. Dust the top of the cake with confectioners' sugar.

Step 6

Serve at once or cover with cling film and refrigerate for up to 5 days. Freeze the cake for longer storage.