Line a 9x9 or 10x10 square baking pan with parchment paper. Set aside.
Remove precooked polenta from packaging and add to a large stock pot along with milk. Cook on medium high heat until polenta melts and turns creamy, about 5 minutes. Use a fork to break up the polenta while it cooks. You may need to add more milk if the polenta is too thick. Whisk in chopped fresh herbs, cheeses, and salt and pepper. Leave a handful of herbs to garnish. Taste and adjust seasonings as needed. Continue cooking polenta until the cheese melts completely, about 3 minutes.
Using a spatula, spread the cooked polenta in an even layer into the baking pan. Place the pan in the freezer for 25-30 minutes, or until polenta is very firm.
Preheat oven to 425 degrees. Remove polenta from the freezer and cut into 1/2 thick fries. If you want thinner cut fries, cut into 1/4 thick pieces. Transfer to lightly greased baking tray, leaving space between the fries. Bake for 10-12 minutes per side, or until golden brown.
Remove fries from the oven and allow them to rest for about 5 minutes. Polenta fries will be very soft when they come out of the oven, but will harden. Once cooled, toss fries with olive oil, salt, and the remaining fresh herbs. Enjoy!