Andrew Feinberg's Slow-Baked Broccoli Frittata

(recipe from Food 52)

10 large eggs
2 1/2 Tbsp. grated Parmigiano Reggiano (I left this out)
1 tsp. kosher salt, plus more to taste (I halved this amount, and still found it to be a little too salty)
40 turns from a black pepper mill (I halved this as well)
7 Tbsp. olive oil, divided
1 medium (1 lb.) head of broccoli (4 cups once trimmed)
1/2 of a red onion, sliced thinly
1 heaping Tbsp. chopped garlic
1/8 tsp. plus a large pinch of dried chile flakes
1 squeeze lemon, to taste, for serving

Preheat the oven to 400F.

Crack the eggs and whisk together with the Parmigiano, salt, and black pepper, and set aside.

Trim 1/2 inch off the stem of the broccoli.  Using a knife, separate all the florets from the base leaving the stem attached and then cut floret pieces in half (you can cut any especially large ones in quarters so all are evenly sized.)  In a 10- to 11-inch oven-safe sauté pan over medium-high heat, cook the broccoli in 4 Tbsp. of olive oil.  Let the broccoli develop a nice brown color on one side, then turn everything over and season to taste with salt.

Transfer the pan to the oven and roast the broccoli until tender, 10 to 15 minutes.  In a separate 10- to 11-inch sauté pan, cook the onion in 2 Tbsp. of olive oil, adding salt to taste.  Cook the onions for about 3 to 5 minutes over medium-high heat until lightly browned.  Reserve onions on the side.

Once the broccoli is fully roasted and tender, transfer the sauté pan back to the stovetop and reduce the oven temperature to 300F.

Over medium heat, add 1 Tbsp. of olive oil to the broccoli pan and add the garlic and chile.  Cook the garlic and chile for 1 minute carefully so as not to burn the garlic.  Add the cooked onions to the sauté pan with the broccoli and mix well.  Add the egg and cheese mixture and let cook for 30 seconds over high heat.

Transfer the pan to the 300F oven and let the frittata cook until the eggs are just set.  Should be about 25 to 30 minutes.  Remove the pan from the oven and then turn the frittata out with a rubber spatula onto a serving plate.  Squeeze lemon juice over the top.  Drizzle olive oil and sprinkle Parmigiano over the top to taste, optional.

(Found!  The secret to an amazing frittata: a longer bake in a lower oven!  Amazing custard-like texture.)