Roasted broccoli should be crispy on the outside and tender on the inside. Some reasons it could turn out soggy and mushy include the following:  Overcrowding: Too much broccoli on the baking sheet creates steam and leaves the broccoli soggy. Too much oil: Using too much oil causes steaming and mushy broccoli. Only use a light coating of oil. Not preheating the oven: Forgetting to preheat the oven will prevent proper cooking and lead to soft broccoli. Roasting at too low of a temperature: Keep the oven at between 400 to 425 °F to prevent broccoli from becoming mush. For more tips on how to get the best balsamic broccoli check out the "Tips & Tricks" section above.