Roast the broccolini. Preheat the oven to 400°F (200°C). Toss the cleaned and trimmed broccolini with olive oil, salt, and pepper and add it to a baking sheet or roasting tray (optionally covered with baking paper for easier cleanup). Roast the broccolini in the preheated oven until the broccolini is tender and slightly charred (about 15 minutes).
Make the dressing. Whisk together the lemon juice, lemon zest, minced garlic, extra-virgin olive oil, salt, pepper, dried oregano, red pepper flakes, Dijon mustard, and one tablespoon of grated parmesan.
Dress the roasted broccolini. Toss the roasted broccolini with the dressing, place the broccolini on a serving platter, and top with the remaining parmesan and toasted almond flakes. Serve the broccolini while hot, straight to the table.