Heat the oven to 375° F (190° C). Lightly oil an 8-inch (20-cm) springform pan. Line the bottom with a round of parchment and oil it. Dust the inside of the pan with flour and tap out the excess.
In a large bowl, whisk together the flour, cornmeal, baking powder, and salt. In a separate bowl, whisk the oil, egg, milk, lemon zest, 1 cup sugar, and almond extract, mixing until thoroughly blended.
Pour the wet ingredients into the bowl of dry ingredients and whisk until just combined. Do not overmix. Scrape the batter into the prepared pan. Set the pan in the oven to bake for 15 minutes.
Make the blueberry topping: Combine the blueberries, sugar, and flour in a bowl. With a fork, mix the ingredients, lightly crushing some of the blueberries and mixing until they are nicely coated. Stir in the almonds.
When the timer dings slide the oven rack out and quickly scatter the blueberry and almond mixture over the top of the cake (discard any flour-sugar mixture left in the bowl). Return the cake to the oven to finish baking for 20 to 30 minutes, until the top is golden-brown, and the cake is puffed up around the fruit. A cake tester inserted into the center should come out clean.
Transfer the cake to a wire rack and let cool 15 minutes. Remove the ring from the pan and let the cake cool another 20 minutes, or until cool enough to handle. Carefully invert the cake onto another rack and remove the bottom and the round of parchment. Re-invert onto the rack to cool completely. Transfer the cooled cake to a serving plate and dust with confectioners' sugar right before serving. Serve with a scoop of vanilla ice cream or a dollop of yogurt if you like.