Trim the bottoms of the broccoli stems and cut off the broccoli heads. Cut the broccoli heads into quarters. Peel the broccoli stems and cut them into quarters crosswise.

Bring a large pot of lightly salted water to a boil. Reduce the heat to medium and cook the broccoli until tender when cut with a paring knife but still slightly firm, about 5 to 6 minutes.

Transfer the cooked broccoli to a large bowl filled with cold water to stop the cooking process. Drain well.

Arrange the broccoli in a colander with the florets facing down towards the holes of the colander and allow the broccoli to drip for at least 30 minutes.

In a large serving bowl, whisk together the garlic, lemon juice, rice vinegar, Dijon mustard, red pepper flakes, salt, and black pepper until well combined.

Slowly drizzle in the olive oil while whisking rapidly until the dressing is thick and creamy. Adjust the seasoning to taste with salt, black pepper, and crushed red pepper flakes.

Toss the chilled broccoli with the dressing. Let it stand for 5 to 10 minutes to marinate, then toss again. For a cold salad, refrigerate for up to an hour before serving. Enjoy your flavorful broccoli salad!