Preheat oven to 325°F (160°C) and grease a 10-cup Bundt pan.

Whisk together flour, 1 ½ cups sugar, baking powder, and salt in a large bowl.

In a separate bowl, cream 1 cup softened butter and the remaining sugar; beat in eggs one at a time, then add vanilla extract.

Gradually add the dry ingredients to the wet mixture, alternating with milk, mixing until just combined. Pour the batter into the prepared Bundt pan.

Bake for 60-70 minutes, or until a wooden skewer inserted into the center comes out clean; cool in the pan for 10 minutes before inverting onto a wire rack.

In a small saucepan, melt ½ cup butter, 1 cup sugar, and ¼ cup water over medium heat, stirring until the sugar dissolves.

Bring the mixture to a boil without stirring and cook until it turns an amber color, which should take about 5-8 minutes.

Remove the saucepan from heat and carefully whisk in the heavy cream, ½ tsp vanilla extract, and ½ tsp sea salt until the sauce is smooth.

While the cake is still warm, slowly pour the warm salted caramel butter sauce over it, allowing it to soak in. Let the cake cool completely before serving.