Preheat your oven to 350°F and grease a 9x13 baking dish really well. Mix together the flour, baking powder, and salt in a small bowl, then set aside. This keeps your cake from getting any weird lumps when you combine everything.

Cream the softened butter and sugar together until it looks pale and fluffy—about 3 minutes with an electric mixer. Add the eggs one at a time, beating well after each addition, then stir in the vanilla extract and lemon zest for that citrus punch.

Alternate adding the flour mixture and milk to your butter mixture, starting and ending with flour (so flour, milk, flour, milk, flour). Fold in the fresh blueberries gently using a spatula so they don't break apart. I always fold mine in super carefully right at the end.

Pour the batter into your prepared pan and smooth the top with a spatula. Bake for 30-35 minutes until a toothpick inserted in the center comes out clean or with just a few moist crumbs attached (don't panic if it looks slightly underdone—it firms up as it cools).

While the cake bakes, whisk together the softened cream cheese, 2 tablespoons lemon juice, and 1/4 cup more sugar until smooth and spreadable. This is your poke cake frosting situation that'll soak right into those warm layers.

Pull the cake from the oven and let it cool for exactly 5 minutes—this is crucial timing. Using a fork or skewer, poke holes all over the entire surface, really going for dense coverage so the filling reaches everywhere.

Spread the cream cheese mixture evenly over the warm cake, letting it seep into all those poke holes you just made. The warmth helps it sink in beautifully, creating that signature poke cake texture throughout. Let it cool completely before serving, then refrigerate for at least 2 hours.