Start by preheating your oven to 350°F (175°C), ensuring that the oven rack is positioned in the center for even baking.

Place the ½ cup of unsalted butter into a 13x9 inch baking pan. Put the pan into the preheating oven to melt the butter. This should take about 5-7 minutes. Carefully remove the pan once the butter is melted, set aside.

Meanwhile, prepare the blueberry mixture. In a medium saucepan, combine 4 cups of fresh blueberries, 1 cup of sugar, 1 tablespoon of freshly squeezed lemon juice, and ¼ cup of water. Stir this mixture together to ensure the blueberries are well coated with sugar.

Place the saucepan on the stove over medium-high heat. Allow the mixture to come to a gentle boil, stirring occasionally to prevent the sugar from burning.

Once the mixture has reached a boil, remove the saucepan from the heat and set it aside for later.

In a large mixing bowl, combine 2 cups of all-purpose flour, 4 teaspoons of baking powder, 1 teaspoon of salt, and 1 ½ cups of sugar. Mix these dry ingredients together until they're evenly distributed.

Pour 2 cups of milk into the bowl with your dry ingredients. Stir this mixture together until it forms a smooth batter. Be careful not to overmix as it can make your final product tough.

Pour the batter directly into the pan containing the melted butter. Do not stir the batter and butter together. The butter will rise to the top during baking, creating a lovely, golden crust.

Use a slotted spoon to scoop out the blueberries from your saucepan. Distribute the blueberries evenly over the top of the batter. The reason we use a slotted spoon is to leave behind most of the liquid in the pan, to prevent the batter from becoming overly moist.

Bake in the preheated oven for 30-35 minutes, or until the top is golden brown and a toothpick inserted into the center of the cake comes out clean.

Let the blueberry cake cool for a bit before serving. Enjoy it warm, maybe with a scoop of vanilla ice cream or a dollop of whipped cream. Enjoy!