I used instant espresso from caffetucano.com.
Put one cup of espresso powder in the custard. And added almonds and almond extract as usual (2 cups slivvered almonds and 2.5 T extract.) The mix was for a gallon.
I am the only one who did not like the result. The espresso flavor was strong, but tasted like instant - imagine that.
Next time I will follow MK's infusion method.