Do I need to blanch green beans before roasting?
Nope. Roasting from raw gives you better texture and less mess. Just trim, dry well, oil, season, and roast.
Do I trim both ends of green beans?
Totally up to you. I usually just trim the stem end (the tough side). If the tail end looks dry or stringy, go ahead and trim that too.
How do I keep roasted green beans from getting soggy?
Three things: dry the beans really well, do not overcrowd the pan, and roast hot. If the beans are piled up, they steam instead of blister.
Can I use frozen green beans?
You can, but they will be softer and release more moisture. Roast straight from frozen on a very hot pan, do not overcrowd, and expect you may need a few extra minutes. You will get more tender beans with fewer crisp spots.
Why add garlic halfway through?
Garlic can burn fast at 425°F. Adding it after the beans have started roasting gives you that sweet, toasty garlic flavor without bitterness.
What if my beans are getting too dark before they are tender?
Your oven may run hot or the beans may be very thin. Drop the temp to 400°F and roast a few minutes longer, or pull the thinner beans early if you have a mixed batch.