Trim 2 heads broccoli; slice from the stem end into thick steaks (some florets will fall off). Toss with olive oil and salt. Roast on a preheated baking sheet at 450 degrees F until browned, 15 minutes. Whisk 1/4 cup olive oil, 2 tablespoons blood orange juice and 1 tablespoon lemon juice; season with salt and red pepper flakes. Drizzle over the broccoli; top with parsley, red onion and feta.