Creme anglaise isn’t listed as an ingredient for the strawberry mousse, but it is in the directions. Is this supposed to contain cremation anglai...

I think step 18 is supposed to be stir the gelatin into the strawberry puree, not into a second portion of creme anglaise.

I suspect in step 18, that strawberry purée was the intended ingredient rather than crème anglaise but I do hope that author, the redoubtable Erin McDowell :) , will be able to answer personally.

Similar to carpenters' rule, to measure twice and cut once.
Read the recipe thoroughly, at least once, maybe twice...for ingredients, timing (on bread or fancy entrees, sometimes need to start day before serving), method,
Here (and in some other sites), also read the comments for ideas, success, problems other cooks have encountered.
In this recipe, there is a link in the introduction to a creme anglaise recipe.