Heat olive oil
First you need to heat one tablespoon of extra virgin olive oil. Take a large skillet and apply medium to medium-high heat for this purpose.
Next you need to add one finely chopped shallot. You are required to cook it for almost five minutes and reduce the stove heat to medium. Continue cooking until the shallot softens. Remember to stir while cooking.
Add garlic cloves
You need to add two minced garlic cloves after cooking the shallot. Keep stirring as you cook the garlic for a minute.
Fluff up the flour
Whisk the flour into the large skillet containing the shallot, garlic and oil. You need to add two and half tablespoons of flour and then cook for a minute.
Now add milk in the large skillet and bring it to a gentle simmer. You are required to continue whisking it until the sauce becomes thick. Remember to bring the heat to low and simmer for a minute as you whisk the milk.
Add pesto and season with salt and pepper
After whisking milk, add ¼ cup of pesto to the sauce. Continue stirring over low heat while adding the pesto. You can season to taste with salt and pepper.
Now you can serve the creamy pesto sauce with the pasta of your choice. To further liven up the taste, you can add shavings of Parmesan cheese on the top.