I made these in my cast iron skillet and they were absolutely delicious!
If you don't have a cast iron skillet, you can use a non-stick, but I highly recommend cast iron. It's naturally non-stick, inexpensive and quite easy to clean after cooking with a quick rinse of hot water and a some coarse salt and paper towels. Just dry thoroughly after each use and coat lightly with oil and you have it ready for next time.
The portobellos were seasoned with 365 Organic Soy Ginger Sauce. It's a brand carried by Whole Foods Market and I love the flavor!
3 large portobello mushroom caps
1 tsp extra virgin olive oil
4 TBS Organic Soy Ginger Sauce
1/2 cup cherry or grape tomatoes, sliced in half
Heat your cast iron skillet (or other skillet) over medium heat with 1 tsp olive oil until pan is hot. Add mushrooms top-side down and cook 5 minutes each side. Add the Soy Ginger Sauce and continue to cook. Add tomato halves and cook until mushrooms are a nice dark brown color and tomatoes are soft.