Instructions

• Pour the sweetened condensed milk into a medium saucepan. Cook over low to medium-low heat, stirring constantly (or very frequently) until it turns a light caramel color, about 30 minutes. If it clumps, transfer to a blender or food processor and pulse until smooth. Remove from heat and let the dulce de leche cool to room temperature while you continue.
• Preheat the oven to 350°F. Lightly grease a 9×13-inch baking pan and line the bottom with parchment, leaving an overhang on two opposite sides for easy removal.
• In the bowl of a stand mixer (or a large bowl with an electric hand mixer), combine the melted butter, 1/2 cup brown sugar, and 3/4 cup granulated sugar. Beat until combined, about 1 minute.
• Add the 2 large eggs and 1 teaspoon vanilla extract. Beat until incorporated.
• Add 2 3/4 cups all-purpose flour, 1 teaspoon baking powder, 1 teaspoon baking soda, and 1/2 teaspoon kosher salt. Mix on low speed just until you no longer see dry streaks or speckles of flour.
• Scrape the dough into the prepared pan and press it evenly into the bottom and up to the edges using your fingers or an offset spatula. Smooth the surface as best you can.
• In the same mixer bowl (no need to wash), add 8 ounces room-temperature cream cheese, 1/4 cup white sugar, 1 large egg, and a pinch of salt. Beat until mostly smooth, about 2 minutes.
• Pour the cream cheese mixture over the pressed dough and spread it into an even layer.
• Use a small spoon or teaspoon to drop small dollops of the cooled dulce de leche onto the cream cheese layer, spacing them about 1 inch apart.
• With a butter knife or skewer, swirl the dulce de leche into the cream cheese in loopy strokes until the surface is marbled.
• Bake in the preheated oven for 25 to 30 minutes, until the edges are set and the center is only a little jiggly.
• Remove from the oven and let the bars cool completely in the pan on a wire rack, about 1 hour. Sprinkle with sea salt, use the parchment overhang to lift the slab from the pan, and slice into bars.