Seared Broccoli and Potato Soup

INGREDIENTS

1/2 cup

olive oil, plus more as needed

heads broccoli (about 2 pounds), separated into small florets, stems peeled and diced

2 1/2 tsp

kosher salt, more to taste

2 tbsp

unsalted butter

large Spanish onion, diced

5 cloves

garlic, chopped

1/2 tsp

black pepper, more for finishing

1/4 tsp

red pepper flakes

1/2 lb

potatoes, peeled and thinly sliced

1/4 tsp

finely grated lemon zest

1 1/2 tbsp

fresh lemon juice, more to taste

Grated Parmesan, to finish

Flaky sea salt, to finish