Smoked Salmon on Portobello with Watercress

Serves 4   1/2 Tbsp. olive oil 1/2 Tbsp. grass-fed butter 4 portobello mushrooms 4 oz. wild smoked salmon Cream cheese Red onion diced Tomato sliced Watercress leaves   Saute portobello mushrooms evenly on each each side until soft. Spread cream cheese on each, then...