Step 1

In a large cast iron skillet, heat 2 tbsp olive oil briefly over medium heat. Add chopped onions and saute until they soft and nicely caramelized (5 to 7 minutes). Add garlic and toss another 30 seconds. Remove onions and garlic to a side plate for now.

Step 2

Add remaining extra virgin olive oil, and if needed raise heat to medium-high, till oil is shimmering but not smoking. Add brussels sprouts flat-side down first. Cook and do not stir or turn over until bottoms crisp up, turning a nice golden brown or even charred (do this to your liking, I like my brussels sprouts pretty charred.)  Turn over on the other side and cook another 5 to 6 minutes until crisp.

Step 3

Toss in the cooked onions and garlic. And add a generous sprinkle of kosher salt.

Step 4

Transfer to a serving dish. Finish with grated Parmesan and toasted pine nuts if using. Serve immediately.