For Caramel Cake Layers:

3/4 cup (170g) butter, softened at room temperature

1 1/2 cups (300g) white granulated sugar

4 large eggs

1 teaspoon (5ml) vanilla extract

14-ounce can (396g) dulce de leche, softened

1 1/3 cups (315ml) milk

2 cups (250g) all-purpose flour

4 teaspoons (16g) baking powder

1/2 teaspoons salt

For Salted Caramel Buttercream:

2 cups (453g) butter; softened at room temperature

14-ounce can (396g) dulce de leche

1/4 teaspoon salt

14-ounce can (396) dulce de leche, for filling

For Sugar Garnish:

1 cup (200g) white granulated sugar

1/2 cup (118ml) water

1) Preheat oven to 350F. Line three, 8-inch cake rounds with parchment paper; or, two, 9-inch cake rounds. Set aside.

2) Prepare the cake layers. In a large bowl, cream together the softened butter and sugar until light and fluffy. Add the eggs, vanilla and dulce de leche. Microwave the caramel for 30 seconds to soften it. Mix all ingredients together until creamy, then pour in the milk. In a separate bowl, combine the dry ingredients: flour, baking powder and salt. Add the flour into the batter in small amounts and whisk after each addition. Whisk only until flour is incorporated.

3) Divide the cake batter evenly between the prepared pans. Bake in preheated oven for 35 to 40 minutes, or until a toothpick inserted into the center comes out clean. Remove cakes from pans and allow them to cool completely. Once cooled, use a long, serrated knife to level the cake layers.

4) While cakes are baking, prepare the crystallized sugar garnish. Combine the sugar and water in a small saucepan and cook over medium heat, not stirring, until sugar caramelized into deep amber color. Pour the sugar syrup over a baking sheet lined with parchment paper. Use a spatula to spread the syrup as it cools. Allow the syrup to cool completely and harden before handling. Break the candy into shards of different sizes.

5) Prepare the buttercream once layers have cooled. Place softened butter into a stand mixer bowl and whisk until light and fluffy. Then add the dulce de leche and a few pinches of salt. Add less salt first, then taste and add more to taste. Whisk buttercream until it's light and fluffy.

6) Assemble the cake. Spread each layer first with a generous amount of dulce de leche, then add the caramel buttercream. Frost the top and sides of cake and smooth over with a flat spatula. Transfer the remaining frosting into a pastry bag. Decorate the sides with the broken sugar.

7) Keep cake refrigerated and remove from fridge about 1 to 2 hours prior to serving to allow the cake to soften.