In a small saucepan, bring 1/2 cup of water to a boil. Remove from the heat, add the poppy seeds and cover. Let stand for 1 hour. Scrape the seeds into a blender and pulse until lightly crushed.
Preheat the oven to 350°. Lightly grease and flour an 8-inch square baking pan, tapping out any excess flour. In a medium bowl, whisk the 1 1/3 cups of flour with the baking powder and salt. In a large bowl, using a handheld mixer, beat the butter with the granulated sugar at medium-high speed until fluffy, about 3 minutes. Add the poppy seed mixture and beat at medium speed until just combined. Add the eggs to the batter one at a time, beating well between additions. Beat in the vanilla and almond extracts. Using a wooden spoon, stir in the flour mixture until just incorporated. Scrape the batter into the prepared pan.
Bake the cake for about 45 minutes, until the top is golden and a toothpick inserted into the center comes out clean. Let the cake cool in the pan for 10 minutes, then invert it onto a wire rack and let cool completely, about 2 hours. Dust the cake with confectioners’ sugar, cut into squares and serve.
The poppy seed cake can be kept in an airtight container at room temperature for up to 3 days.