Place potatoes in a pot and cover with salted water. Bring to a boil, turn down heat to medium. Boil for 10 minutes and drain.
Slice flank steak against the grain into about ¼ inch slices.
Mix marinade and stir into meat slices. Cover and put aside.
Preheat oven to 450°
Chop fresh seasonings and separate into two groups.
In large skillet, melt 1T olive oil and 2T butter.
Add half of the garlic and seasonings. Saute for 30 seconds.
Add potatoes and saute for 5 minutes, stirring well so that potatoes are well covered in butter. Pour onto edged sheetpan.
Place potatoes in oven and cook for 10 minutes.
Using same skillet, melt remaining butter and olive oil. Add garlic and spices.
Stir in meat slices until well covered, leaving any extra marinade behind.
Remove potatoes from oven and spoon meat slices onto the other half of the sheetpan.
Return to oven and cook for 10 more minutes.
Pour any remaining marinade into hot skillet and heat through.
Spoon sauce over meat and potatoes and serve.