This easy and delish recipe is courtesy of Elise Bauer at Simply Recipes, https://www.simplyrecipes.com/recipes/fresh_basil_pesto/. It is important to keep basil pesto covered tightly. Ideally it should be kept in an airtight container like a glass container with a locking lid as it darkens when exposed to air.

Ingredients

2 cups fresh basil leaves, packed (can sub half the basil leaves with baby spinach)
1/2 cup freshly grated Romano or Parmesan-Reggiano cheese (about 2 ounces)
1/2 cup extra virgin olive oil
1/3 cup pine nuts (can sub chopped walnuts)
3 garlic cloves, minced (about 3 teaspoons)
1/4 teaspoon salt, more to taste
1/8 teaspoon freshly ground black pepper, more to taste

Instructions

Place the basil leaves and pine nuts into a food processor and pulse several times.
Add the garlic and Parmesan or Romano cheese and pulse several times more.
Scrape down the sides of the processor periodically.
While the food processor is running, slowly add the olive oil in a steady stream. Adding the olive oil slowly will help it emulsify and keep it from separating from the mixture.
Scrape down the sides of the processor to ensure all of the ingredients are mixed together.
Add salt and pepper to taste.