Vegan Portobello Steaks with Cowboy Butter

0 In a large mixing bowl, whisk together the marinade. Add the soy sauce, lemon juice, olive oil and broth to the bowl and whisk. Then add the garlic, horseradish, chives, parsley, salt and pepper to the bowl and whisk again. 
1 Put the Portobello mushrooms in the bowl and press them down into the marinade. I like to place a bowl on top of them and put something heavy in the bowl to weigh them down. 
2 Place the mushrooms in the marinade into the fridge and let marinate for 4-6 hours. I like to leave them over night, but they can sit as long as you want. I think the longer the better. 
3 Now, make the cowboy butter. In a small mixing bowl, add the melted vegan butter, and then all the remaining cowboy butter ingredients. Whisk to combine. 
4 Then place in the fridge as well to chill. It will become solid again. 
5 When ready to make the Portobello steaks, heat a large non-stick skillet on medium high. 
6 Remove the mushrooms from the marinade and either discard the marinade or save for future use. I recommend scooping some of the garlic and herbs out of the marinade to sauté as well. 
7 Place the mushrooms in the hot skillet, and saute, reducing heat as need. Cook for 5 to 7 minutes per side or until the mushrooms are brown and juicy. 
8 Serve with a small scoop of the chilled cowboy butter on top and veggies on the side if desired.