Cinnamon-Brown Sugar Pop-Tart® Cake
Ingredients:
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cooking spray
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6 cinnamon-brown sugar toaster pastries (such as Pop-Tarts®)
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5 tablespoons unsalted butter, melted
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¾ cup brown sugar, divided
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1 tablespoon all-purpose flour
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4 teaspoons ground cinnamon, divided
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1 teaspoon milk
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½ cup unsalted butter, softened
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½ cup white sugar
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1 egg, separated
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1 ½ teaspoons vanilla extract
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1 cup all-purpose flour
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1 ½ teaspoons baking powder
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½ teaspoon salt
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¾ cup milk
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1 ½ teaspoons white vinegar
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1 cup cream cheese frosting, or to taste