Balsamic vinegar is the secret ingredient here.

2 c roughly chopped rapini
2 cloves garlic, minced
1/2 c toasted pine nuts or walnuts
2 T balsamic vinegar
1/2 – 3/4 c extra-virgin olive oil, to taste
salt and pepper, to taste

1. Bring a large pot of water to the boil. Add chopped rapini and boil for about 5 minutes. Drain well.

2. Put drained rapini in a food processor with garlic, pine nuts, and vinegar. Process until finely chopped. With machine running, slowly add oil until the mixture reaches a pesto-like consistency, or to your preference. Add salt and pepper to taste and process briefly to combine. Taste for seasonings.