Preheat the oven to 400 degrees or to the temperature that is on the package of fries.
On a sheet pan, place parchment paper. Spread the whole bag of frozen french fries to the pan in a single layer.
Cook according to package directions, mine took about 30 minutes flipping halfway through.
In the last 5 minutes of cooking, make the pesto sauce to go on top.
In a heatproof cup or glass measuring cup melt the butter.
To the melted butter add the minced garlic and Parmesan cheese.
Add the prepared pesto sauce.
Finally, pour in the olive oil. Stir to combine completely.
Take the french fries out the of the oven and pour the pesto sauce over the fries. Put back into the oven for 5 minutes.
Take out and serve individually with parmesan-romano cheese sprinkled on it. Enjoy!