Preheat your oven to 350°F (175°C).
Grease your baking dish lightly with butter or cooking spray.
In a mixing bowl, combine the melted butter and sugar. Whisk together until well blended. Add the eggs one at a time, whisking after each addition until fully incorporated. Stir in the almond extract.
Sift the flour into the wet mixture, stirring gently until just combined.
Gently fold in the sliced almonds.
Pour the batter into your prepared baking dish and smooth the top with a spatula. Bake for about 20-25 minutes, or until the top is golden and a toothpick inserted into the center comes out clean.
Allow the cake to cool in the dish for a few minutes, then transfer it to a wire rack. Once cooled, dust the top with powdered sugar and serve.