Add the basil to a food processor and pulse until minced. Add the almonds and a big pinch of salt and blend until a paste forms.
Add the extra virgin olive and pulse until completely incorporated. Add a few splashes of water and pulse after each addition until desired consistency is reached. You want it to be thick, but pourable. Taste and season with salt and pepper.
Stew the beans:
Heat 1 tablespoon extra virgin olive oil in a large pot over medium heat. Add the onion and sauté for 5–6 minutes until it begins to soften. Add the beans and season with salt, pepper, and crushed red pepper. Add 2 cups of water and bring to a boil. Reduce heat and simmer for 20 minutes until thickened. taste and season with salt, pepper, and more crushed red pepper if you like.
Finish the beans:
Pour the pesto into the beans and turn off the heat. Let stand for 5 minutes and season once more to taste.
To serve:
Ladle the beans into bowls and garnish with more basil leaves and slivered almonds on top. Enjoy!