Add potatoes to a large, microwave safe bowl. Cover with a plate or hard (microwave-safe) plastic cover to trap the steam in the bowl. Microwave for 10 minutes, stirring about halfway through.
Pat the potatoes as dry as possible, then add kosher salt to bowl. Vigorously stir the potatoes and kosher salt to rough up the edges and help develop the starch on the outside of the potatoes. This should take 2-4 minutes of stirring.
Pre-heat oven to 425° (or 400° if you have a convection oven).
Add olive oil to a small sauce pan and heat over medium-high heat until shimmery. Add garlic and chopped rosemary. Saute for 2-3 minutes until softed and garlic is golden brown. Add butter to melt, then remove from heat and strain the garlic and rosemary from the liquid, reserving it for later.
Toss potatoes with the infused olive oil mixture until coated evenly. Season with Flavor God Garlic Lover's seasoning, then spread into an even layer on a large baking sheet.
Roast the potatoes for 20 minutes, then toss them with a spatula and roast for another 20 minutes. Add reserved garlic and rosemary mixture, tossing the potatoes to coat evenly. Roast for a final 20 minutes.
Top with fresh chopped parsley and flakey sea salt before serving, if desired.