Preheat the oven to 375°F (not fan-assisted). Grease an 8-inch springform pan and line the bottom with a round piece of parchment paper. Set aside. In a large bowl, using an electric mixer or a stand mixer fitted with the paddle attachment, beat the butter and white sugar on medium speed until the mixture is pale and fluffy. Add the eggs one at a time, beating well after each addition and scraping down the sides and bottom of the bowl to ensure everything is fully incorporated. With the mixer on low speed, mix in the all-purpose flour, ground almonds, and baking powder until just combined. Spoon the thick batter into the prepared springform pan and smooth the surface with a spatula. Prepare the pears by peeling them and cutting each in half lengthwise from the stem to the base. Use a small spoon to remove the core and scrape out the thick spine running up to the stem. Set the pears aside. Arrange the pear halves on top of the batter in a circular pattern, cut side down and with the narrow ends facing the center. Sprinkle the flaked almonds evenly over the top. Bake in the preheated oven for about 35 minutes, or until a skewer inserted into the center comes out clean. Allow the cake to cool completely in the pan, then run a knife around the edges and carefully remove the springform ring and base. Dust the cake with icing (confectioners’) sugar before serving.