Preheat your oven to 350°F and grease a 9-inch square baking pan with a little butter or cooking spray. Let the dry ingredients sit together for a second — it sounds boring but mixing flour, baking powder, and salt beforehand means no lumpy streaks in your final cake.

Cream together the softened butter and 1 cup sugar in a large bowl until it looks pale and fluffy, about 3 to 4 minutes. I always forget this step matters, but it does — the air you beat into the mixture makes the cake rise properly. Beat in your 2 eggs one at a time, then add the vanilla bean paste and lemon zest.

Add your flour mixture and milk alternately to the egg mixture, starting and ending with flour. Go slow here — alternate in three rounds so everything mixes evenly without overdoing it. Gently fold in the 1/2 cup fresh blueberries right at the end using a spatula, being careful not to crush them.

Pour the batter into your prepared pan and bake for 38 to 42 minutes until a toothpick inserted in the center comes out clean or with just a few crumbs. Don't panic if it looks slightly underbaked — that's actually perfect for a poke cake. Let it cool for about 5 minutes, but don't wait too long.

While the cake's still warm, use a fork or wooden skewer to poke holes all over the surface — and I mean really poke it, don't be shy. You want at least 30 to 40 holes because that's where the syrup goes. My 6-year-old absolutely loved doing this part last summer.

Make your syrup by whisking together 1/2 cup powdered sugar, 2 tablespoons lemon juice, and 1 tablespoon cornstarch in a small bowl until smooth. Slowly pour this mixture over the entire warm cake, letting it seep into every hole. The cornstarch keeps it from being too runny, which used to be my problem before I figured that out.

Dust the top with a pinch of ground cinnamon for color and a subtle spice note. Let the cake cool completely before serving — it actually tastes better the next day when the flavors have time to settle and deepen.