with balsamic caramelised pesto
4 servings
  • 4 Brioche Buns

For the Balsamic Caramelised Onions

  • 3 large red onions
  • 2 tablespoons olive oil
  • 1 tablespoon unsalted butter
  • 1 tablespoon Balsamic vinegar
  • 1 heaped teaspoon brown sugar

For the Walnut Pesto

  • 1 cup fresh flat leaf parsley
  • ¼ cup roasted walnuts
  • 1 small garlic clove, crushed
  • ½ cup extra virgin olive oil
  • ¼ cup parmesan, finely grated

For the beef patties

  • 800g beef mince (makes 8 x 100g patties or 4 x 200g patties)
  • ¾ cup breadcrumbs
  • 1 egg yolk
  • 1 clove garlic, crushed
  • salt and pepper
  • 1 cup spinach leaves (approx. 50g)
  • 4 – 8 slices of tomato (you can use 1 or 2 per hamburger)
  • 4 – 8 slices of Castello Burger Blue cheese slices (you can use 1 or 2 per hamburger)




Caramelised onions:

  • Use a mandolin to slice the onions.
  • Add olive oil and butter to a pan over low heat, add in onions and stir them through the oil and butter. Cook onions, stirring intermittently, until caramelisation takes place. This can take up to half an hour so make sure to keep an eye on them so that they don’t stick to the pan.
  • Just prior to removing onions from the pan, add in balsamic vinegar and brown sugar, turn the heat up to medium and cook through for a further 3-4 minutes. Remove from heat and set aside.


  • Whilst the onions are cooking down, you can make the pesto. Place all of the ingredients into a food processor and blitz to reasonably smooth consistency. Taste the pesto and adjust accordingly. It might need a little more oil or parmesan depending on preferences for taste and texture. Set aside.

Beef patties and Building:

Combine all ingredients in a large bowl and knead gently. Depending on the size of the patties you are making, take 100-200g of the meat mixture and press into burger patty shapes.

Slice the tomatoes and rinse the spinach leaves.

Cook off the burger patties on the stove / grill over medium heat and add a slice of Castello Burger Blue to each one, once you have flipped each patty once. Allow the cheese to melt lightly over the edges of the patty and then remove and stand before serving.

Slice your brioche buns open, add pesto, onions, tomato, spinach and finally the beef and cheese patties. Finish with the top of the brioche bun. Repeat for all burgers. Note: brioche can be served toasted or fresh.

Recipe created by Phoodie. For more information and images visit Phoodie's blog here