Wash and chop broccoli into florets. Place on baking sheet. I prefer to use my Silpat because it doesn't stick, but if you don't have one, just rub a little olive oil on the pan first and then place the broccoli on it.
I place the broccoli in a mound on the baking sheet, drizzle the olive oil over, sprinkle with salt and pepper, and grate the garlic clove(s). I then use clean hands to toss the broccoli (directly on the baking sheet) to evenly coat. Spread the broccoli evenly out before placing into the oven. If the broccoli is crowded it will not roast evenly.
Place in oven that has been preheated to 425. Roast for 10-15 minutes, tossing gently half way through cooking. The size of the broccoli florets will impact the cooking time. The larger the floret the longer it will take. You are looking for the broccoli to become crisp tender (I test with a fork) and edges begin to darken.
This is not a recipe that you need to follow closely when it comes to measurements. I rarely measure, and instead adjust based on the amount of broccoli.