Heat the olive oil in a heavy-bottomed saucepan over medium heat.
Add the ginger and garlic and saute until fragrant, 3-5 minutes, stirring frequently to prevent burning.
Add the ketchup, Worcestershire, Tabasco, malt vinegar and Coke and gradually bring to a boil.
Reduce heat and let sauce simmer until thickened.
Add the mustard, espresso powder, brown sugar, black pepper, garam masala and tandoori spice and let reduce for another 10-15 minutes. The sauce should be a dark red-brown and fairly thick.
Let cool completely, then store in glass jars until ready to use.