01 -
Preheat the oven to 350°F (175°C). Line a 9 x 9 inch baking pan with parchment paper, letting the paper hang over the sides for easy cake removal.
02 -
Combine granulated sugar and lemon zest in a large bowl. Massage the zest into the sugar for 20 to 30 seconds to release oils and enhance flavor.
03 -
Add butter and oil to the sugar mixture. Using a hand or stand mixer, beat on medium speed until light and fluffy, about 2 minutes. Scrape the sides of the bowl. Add eggs one at a time, mixing well after each. Scrape down the sides of the bowl as needed. Then add lemon juice and vanilla, mixing on low speed until combined.
04 -
In a separate bowl, whisk together flour, baking powder, baking soda, salt, and poppy seeds. Add dry ingredients to the wet mixture in three additions, alternating with the sour cream and milk. Begin and end with dry ingredients, mixing gently to avoid overmixing.
05 -
Spoon the batter into the prepared pan, leveling the top with an offset spatula.
06 -
Bake for 30 to 35 minutes or until the top is golden and a toothpick inserted in the center comes out clean. If browning too quickly, cover loosely with aluminum foil. Avoid overbaking to prevent dryness.
07 -
Remove the cake from the oven and let it cool in the pan for 30 to 45 minutes. Use the parchment overhang to lift it onto a wire rack. Cool completely before glazing.
08 -
Whisk together powdered sugar with milk or lemon juice until smooth. Add a splash of vanilla if desired. Pour glaze over the cooled cake.