Recipes Nugget Markets Signature Recipes
California Walnut Crostini with Baby Arugula and Caramelized Onions
- Prep time
- 15 minutes PT15M
- Cook time
- 30 minutes PT30M
- Yield
- 24-30
- Difficulty

Having a dinner party? Start your guests off with this delicious walnut crostini. The sweetness of the caramelized onions really compliments the sharp flavor of the arugula.
Ingredients
- For the caramelized onion:
- 1 tablespoon butter
- 1 teaspoon extra virgin olive oil
- 1 medium to large yellow onion, peeled, halved and thinly sliced
- Salt and pepper
- For the seasoned California walnut spread:
- One 3-inch chunk of carrot
- One 3-inch chunk of celery
- 1 shallot, peeled and cut in half
- 1 large bay leaf
- 2 ½ cups milk
- Salt and pepper
- 2 ½ cups (8 ounces) toasted California walnut halves and pieces
- For the crostini and for serving:
- About half a sourdough baguette, cut diagonally into slices about ¼-inch thick (for 24 – 30 slices)
- ¼ - ⅓ cup extra virgin olive oil
- 1 or 2 cloves garlic, peeled
- 1 ½ cups, lightly packed, small arugula leaves (about 1 ounce)
- Salt and pepper
Preparation
To prepare the caramelized onion, melt the butter in a medium saucepan over medium-low heat. Add the olive oil and onion, season lightly with salt and pepper and stir to combine.
Cook for 20 – 30 minutes, or more, stirring frequently—it is okay if the onions brown lightly, which gives them color and sweetness, but don’t burn them. When done, the onions will have reduced to about ¼ cup and be a pale golden color. Transfer to a small bowl and set aside.
To prepare the seasoned walnut spread, wrap the carrot, celery, shallot and bay leaf in a double thickness of cheesecloth and tie the bundle securely with twine. Put in a medium saucepan, pour in the milk and season with ¼ teaspoon salt and 1/8 teaspoon pepper. Bring to a simmer over medium-high heat. Add the walnuts, reduce the heat, and poach in the simmering milk for 18 – 20 minutes, stirring once or twice.
Strain, reserving the milk. (Discard the cheesecloth bundle.) While the walnuts are still warm, put them in a food processor. Add 1/3 cup of the reserved milk and puree. Add additional milk by tablespoons, until the mixture is smooth and spreadable. Season to taste with salt and pepper, transfer to a bowl and set aside. (Any remaining milk may be used in a soup or sauce.)
To prepare the crostini, brush the baguette slices lightly with olive oil, put them in a single layer on a baking sheet, and place in a preheated 350ºF oven for about 5 minutes, to dry and crisp. Remove from the oven and gently rub each slice with garlic.
Spread about 1 tablespoon of seasoned walnut mixture on each crostini. In a small bowl toss the arugula with 1 tablespoon olive oil, then season lightly with salt and pepper. Drape a few leaves of arugula over each crostini and top with about 1/2 teaspoon caramelized onions.