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slice of walnut cake with buttercream
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4.46 from 11 votes

Romanian Walnut Buttercream Cake

A festive Romanian walnut buttercream cake with caramelized walnuts, this is one of the most decadent, best walnut cakes you could possibly make.
Prep Time1 hour
Cook Time1 hour
Total Time2 hours
Course: Romanian Cakes and Desserts
Cuisine: Romanian
Servings: 10 -12
Calories: 516kcal
Author: Adina

Ingredients

  • Walnuts:
  • 350 g shelled walnut halves 12.3 oz, See note
  • Caramel:
  • 5 tablespoons granulated sugar
  • Cake:
  • 8 eggs only the egg whites, the egg yolks are for the buttercream
  • 3 tablespoons granulated sugar
  • 1 pinch of salt
  • 1 tablespoon rum optional
  • 2 tablespoons lemon juice
  • Walnut buttercream:
  • 9 tablespoons granulated sugar
  • 200 ml milk 6.7 fl.oz/ ¾ cup + 2 tablespoons
  • 300 g good quality unsalted butter, fat content at least 82% 10.5 oz/ 1 ¼ cups + 1 tablespoon
  • 1-2 teaspoons vanilla extract to taste

Instructions

Walnuts:

  • Roast walnuts: Preheat the oven to 220 degrees Celsius/ 430 degrees Fahrenheit. Line a baking tray with baking paper. Spread the walnuts on the baking tray in an even layer and roast for about 3 or 4 minutes until slightly golden and beginning to be fragrant. Keep an eye on them, they should not get too dark or they will taste bitter. Take out of the oven and let get cold.
  • Grind: When cold, grind them finely either in the food processor or place them in a large freezer bag and crush them with the rolling pin. Set aside.

Caramel:

  • Weigh 100 g/ 3.5 oz/ 1 cup of the roasted and ground walnuts and set them aside.
  • Place a sheet of aluminum foil on a large plate.
  • Make the caramel: Place 5 tablespoons of the sugar in a non-stick pan. Let it caramelize, taking care that it doesn't get too dark. Next, take off the heat and stir in the walnuts you have just weighed.
  • Cool: Spread this mixture on the aluminum foil and let it set completely.

Cake base:

  • Preheat the oven to 180 degrees Celsius/ 350 degrees Fahrenheit. Line the baking tray (about 30x40 cm/ 12x15 inches) with baking paper.
  • Make the batter: Separate the eggs. Set the yolks aside; you will only need them for the buttercream. Beat the egg whites with a pinch of salt until stiff. Add 3 tablespoons sugar, rum (optional), and lemon juice and continue beating until stiff and glossy. Carefully fold in the rest of the ground and roasted walnuts.
  • Bake: Pour this mixture onto the prepared baking tray and bake the cake base for about 20-25 minutes. Let it cool completely, then slice it into 3 equal rectangular parts.

Buttercream:

  • Mixture: Beat the egg yolks with 9 tablespoons of sugar until pale and creamy. Slowly add the milk and incorporate it. Pour the mixture into a saucepan and place it on a very low flame. Stir continuously with a wooden spoon until the mixture thickens, it took me 15 minutes on a very low flame. Set aside, place a piece of plastic foil on top to prevent it from getting skin, and let get cold.
  • Make the buttercream: In the meantime take the butter out of the fridge and let it get soft. Beat the soft butter with the hand-held mixer until light and fluffy. Start adding the cold egg yolk cream, one tablespoon at a time, while beating continuously. Beat in the vanilla extract to taste, as well.

Assemble:

  • Fill cake: Place one slice of the cake base on a rectangular serving platter. Cover with one-third of the buttercream, place another piece of cake on top, cover with another third of the buttercream. Finally, place the third cake slice on top and cover with the rest of the buttercream.
  • Top: Roughly crush the caramelized walnuts and top the cake with them. Let rest in the fridge overnight.

Notes

Always use a digital kitchen scale in baking; it ensures the best results (Amazon affiliate link). Weigh the nuts, measuring walnuts halves in cups is very unprecise, as it all depends on their size.

Nutrition

Serving: 1slice | Calories: 516kcal | Carbohydrates: 27g | Protein: 9g | Fat: 43g | Saturated Fat: 16g | Polyunsaturated Fat: 24g | Trans Fat: 1g | Cholesterol: 179mg | Sodium: 230mg | Fiber: 2g | Sugar: 23g