Pre-heat oven to 400 degrees Fahrenheit.
Prepare the Brussels sprouts by trimming the ends and peeling off the outer layer. Cut the sprouts in half.
Trim the ends off the fresh green beans.
In a large bowl, combine the halved Brussels sprouts and trimmed green beans. Toss them by hand with extra virgin olive oil (EVOO), garlic, salt, and pepper. It's important to coat them thoroughly with the mixture to ensure both an even coating and optimal flavor.
Line two baking pans with foil for easy cleanup.
Evenly spread the tossed Brussels sprouts and green beans on the foil-lined baking pans to prevent steaming during cooking.
Squeeze fresh lemon juice over the vegetables, distributing it evenly.
Place the baking pans in the preheated oven. Cook for 20 minutes, then flip the vegetables for even browning.
Continue cooking for an additional 20 minutes, or until the vegetables reach your desired level of crispiness. If they are already crispy before the full 20 minutes, you can remove them from the oven earlier. Adjust the cooking time based on your preference for texture.