For the Cake:

• 2 cups all-purpose flour
• 2 cups granulated sugar
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1/2 teaspoon salt
• 1 cup unsalted butter, softened
• 1 cup whole milk
• 4 large eggs
• 2 teaspoons vanilla extract

For the Caramel Sauce:

• 1 cup granulated sugar
• 6 tablespoons unsalted butter, cut into pieces
• 1/2 cup heavy cream
• 1 teaspoon vanilla extract
• 1/2 teaspoon salt

For the Crunch Topping:

• 1 cup crushed toffee bits (such as Heath or Skor bars)
• 1/2 cup chopped pecans or walnuts (optional)

For the Frosting:

• 1 cup unsalted butter, softened
• 4 cups powdered sugar
• 1/4 cup caramel sauce (from above)
• 2–4 tablespoons heavy cream
• 1 teaspoon vanilla extract
• A pinch of salt