We used to have a bottle of smth very strong. This is key. It was 50%+. We bought it in duty free in Spain (Majorca I think). It was a biggish bottle. A litre perhaps. Dark glass. Tall rather than puffy. I remember the label was yellowish but could be mistaken.
The drink was strong (well 50%), dark, sweet, aromatic.
We used to add it to coffee.
And it is not Kahlua because Kahlua is only 20%. And it was definitely something Spanish.
Please help me remember