Make sure it's evenly distributed, and then you're good to grill. While it's always best to cook steak from room temperature, you might want to cook it from frozen if this is your only option.

Leftover Portobello Mushroom Steak last in the refrigerator for 3-4 days in an airtight container. They can also be frozen for up to 3 months. My favorite way to reheat leftover grilled portobello ...