Converting integer list object to double list object without changing the structure of the list object

Question

Here is how my data look like.My initial dataset

I want to convert the objects that have integer characteristics to double. When I am using as.double or lapply(mydataset, as.numeric) the list objects are changed to double[25] as shown in the picture.MY dataset after converting to double.

My question is how I can convert the integer object to double keeping the structure of each object 5*5.