Preheat the oven to 350°F (180°C). Grease a 9-inch springform pan and line the bottom with a round of parchment paper. Set aside.

In a medium bowl, whisk together the almond flour, all-purpose flour, baking powder and salt.

In a separate large mixing bowl, beat the butter, oil and sugar together until light and fluffy, about 2-3 minutes. Add the eggs, almond extract, sour cream and vanilla extract. Mix until combined.

Add the dry mixture. Mix on low speed until just combined; do not overmix. The batter will be thick.

Pour the batter into the prepared pan and smooth the top. Sprinkle the sliced almonds and 1 tablespoon of sugar evenly over the top.

Bake for 35-45 minutes, or until the top is golden and a toothpick inserted in the center comes out clean. If the top is browning too quickly, loosely tent with foil during the last 10-15 minutes.

Let the cake cool in the pan for 10-15 minutes, then run a knife along the edges and remove the springform ring. Cool completely on a wire rack. Dust with powdered sugar before serving.