"Strong espresso" refers to a type of coffee that is bold, intense, and has a higher concentration of caffeine. It is more powerful and flavorful than regular coffee. Full definition
Think of it as very strong espresso that is ready to use. (fitfoodiefinds.com)
You're looking for something the color of strong espresso mixed with a splash of cream. (bonappetit.com)
Espresso Hazelnut Shortbread Cookies ~ this buttery shortbread cookie recipe is made with strong espresso and ground hazelnuts for a refined flavor. (theviewfromgreatisland.com)