Even before you pull your Brussels sprouts out of the freezer, you can begin heating up an oiled baking sheet. Pour a thin drizzle of olive oil over the surface of a large baking sheet, and put it in the oven to warm up as the oven heats. A pre-heated baking sheet—with pre-heated olive oil—will help your sprouts cook more rapidly once you stick them in the oven. Pull your sprouts out of the freezer and open the bag. Also pull out large mixing bowl. Pour the Brussels sprouts into the bowl. You may need to use a pair of household scissors to cut open the bag of sprouts if it won’t tear open. In order for frozen vegetables to roast properly, they need to be well-oiled. Pour a generous 1⁄4 cup (59 mL) or 1⁄2 cup (120 mL) over the Brussels sprouts. Once the sprouts have olive oil on them, sprinkle 1–3 teaspoons (4.9–14.8 mL) of salt over them. The amount of salt can vary based on how strong you want the taste of salt to be on the finished sprouts. Any type of salt is fine; you can suit your preference. Common types of salt used include kosher salt or coarse sea salt. Use your hands to toss and roll the Brussels sprouts in the olive oil and salt mixture. Make sure that the salt doesn’t stick together in clumps, but is evenly spread over the sprouts. Each of the frozen sprouts should be evenly coated with olive oil and salt.

Summary:
Drizzle olive oil over your baking sheet. Pour your frozen Brussels sprouts into a mixing bowl. Pour olive oil over the sprouts. Add salt to the oiled sprouts. Toss the sprouts with the oil and salt.