10 ml

http://www.ilmondotownsville.com/Measure-Spoons-Wire-Handles-Set-5-Chef-Inox

is the Icelandic letter eth (Ð, lower case ð), pronounced as a voiced "th," but I have no idea what it means in a recipe except that it could be a word processing coding error.

It includes a dtsp. And, it looks like a double teaspoon, size-wise.

I have never used it.

Maybe the capital D with a line through it is some other form used there?

Anyway, a dessert teaspoon is equivalent to two teaspoons (10 ml). Does that make sense in your recipe?

but the 2 teaspoon measure seems the most logical, given the British/Australian measures of dtsp for 10 ml, tbl at 15 ml, and tsp at 5 ml. It also more or less makes sense in the recipe.

There are sets of measuring spoons that have that measure. I've also seen 1/2 tablespoon measures which equate to 1 + 1/2 teaspoons.

In the day and age with cheap scales accurate to 0.1g, I wish more recipes would reference weight rather than volume.