Lower the oven rack to the lower third position and preheat the oven to 350°F (177°C). Spray the inside of a 10-inch Bundt pan with nonstick spray or grease thoroughly with butter. Set aside.

Sift the flour and cornstarch together into a large bowl. Whisk in the salt, baking powder, baking soda, and poppy seeds. Set aside.

Using a handheld or stand mixer fitted with a paddle attachment, beat the butter on high speed until smooth and creamy—about 1 minute. Add the sugar and beat on high speed for 2 minutes until creamed together fairly well. Scrape down the sides and up the bottom of the bowl with a silicone spatula as needed. Add the eggs and the vanilla. Beat on medium-high speed until combined. Scrape down the sides and up the bottom of the bowl with a silicone spatula as needed. Beat in the lemon zest and lemon juice. With the mixer on low speed, add the dry ingredients in three additions alternating with the buttermilk, beginning and ending with the dry ingredients, and mixing each addition just until incorporated. Do not overmix. The batter will be slightly thick.

Pour/spoon the batter evenly into the Bundt pan. Bake for 40-50 minutes or until a toothpick inserted into the cake comes out clean. Cover the cake loosely with aluminum foil if you begin to see the top browning quickly. Once done, remove from the oven and allow to cool for 10 minutes inside the pan.

Combine the granulated sugar and lemon juice in a small saucepan over medium heat. Stirring constantly, cook until the sugar has dissolved. Remove from heat and set aside.

Invert the slightly cooled Bundt cake onto a wire rack set over a large plate or serving dish. Spoon the syrup on top of the cake. Allow cake to cool, then place on serving plate before topping with icing/glaze. (Next step.)

Whisk the confectioners’ sugar and lemon juice together in a small bowl. Drizzle over cake. Slice and serve.