Preheat your oven to 375°F. Grease and flour your 9x13-inch baking dish and set aside.

In a large bowl, sift together the flour, sugar, baking powder, and salt until well combined.

Add the milk, vegetable oil, beaten eggs, and vanilla extract right into the flour mixture and stir until you have a smooth, semi-thick batter. Don't overthink it — it comes together quickly.

In a small separate bowl, toss your blueberries with the 1 teaspoon of flour until they're lightly coated all over. This little trick keeps them from sinking straight to the bottom while baking.

Gently fold the blueberries into the batter with a spatula — slow and easy, fold don't stir. You want those berries whole and happy in there.

Pour the batter into your prepared baking dish and spread it out evenly.

Bake for 25 to 30 minutes until the cake is lightly golden and mostly set in the center.

Pull it out of the oven and immediately brush the entire top generously with melted butter — don't be shy — then sprinkle the sugar evenly over it.

Back into the oven it goes for another 5 to 10 minutes, until the top is beautifully golden, glazed, and a toothpick inserted in the center comes out clean.

Let it cool for a few minutes before cutting — if you can wait that long. Serve warm with a good dollop of whipped cream.