1Saute mushrooms and onions in olive oil for about 10-15 min till onions are tender. Remove from pan.
2Add 2 c. of beef stock and heat until hot. Reduce heat to med-low. Mix together 2 TBL. of cornstarch with 1 c. of COLD water. Mix till all lumps are gone. Pour into beef stock. Stir with whisk frequently until gravy has thickened. Remove from heat and add mushrooms and onions back into gravy. Mix with spoon to combine.