Heat the oven to 175 C / 350 F. Grease a 23 cm / 9-inch springform pan and line the bottom with parchment paper.

Cream the butter and sugar in a mixing bowl with a hand mixer on medium speed for about 3 minutes, until pale and fluffy.

Beat in the eggs one at a time, then the vanilla extract, mixing until smooth.

Whisk the flour, baking powder and salt together in a separate bowl. Add to the butter mixture in three additions, alternating with the milk, mixing just until combined.

Pour the batter into the prepared pan and smooth the top with a spatula.

Bake for 22 to 25 minutes, until the edges are set and the center springs back but still looks slightly underbaked. A toothpick may come out with a few moist crumbs, that's expected since the cake goes back into the oven.

While the cake bakes, melt the butter for the topping in a 1.5-quart / 1.4 L saucepan over medium heat.

Stir in the sugar and heavy cream. Bring to a gentle simmer and cook for 3 to 4 minutes, stirring often, until slightly thickened and light amber in color. Watch closely here, it darkens fast once it starts to color.

Remove from the heat and stir in the flour, salt and vanilla extract, then fold in the sliced almonds until coated.

Take the cake out of the oven while it's still soft in the center. Spread the warm almond topping evenly over the surface right to the edges.

Return the pan to the oven and bake for 10 to 12 minutes more, until the topping is bubbling and deep golden at the edges.

Cool the cake in the pan on a wire rack for 15 minutes, then run a knife around the edge and release the springform sides. Let it cool completely before slicing.