Preheat oven to 400F.
In a pan over medium heat, add in the extra virgin olive oil. Add in the minced onion and sauté until tender, about 4-5 minutes.
Add the minced garlic into the same pot and sauté until fragrant, about 1-2 minutes.
Add in the flour, dried herbs, sea salt, and black pepper into the same pot. Continuously stir for 1-2 minutes.
Add in the broth and milk into the same pot. Whisk all ingredients together, so that the flour is not in lumps.
Reduce heat and simmer for 8-10 minutes, or until it thickens.
In the meantime, skin the potatoes and slice into 1/8" rounds.
In a medium-sized casserole pan, add in a single layer of the sliced potatoes. Pour in a good portion of the flour batter. Repeat until all potatoes and flour batter is used. (For reference, I used a 9" round casserole dish.)
Cover the casserole pan with aluminum foil and bake for 30 minutes. Uncover and bake for an additional 25-30 minutes. The top should be golden brown and bubbly.
Garnish with freshly-chopped cilantro and freshly-grated parmesan cheese. Serve warm.