"In the easy way" is not found after "English", only "the easy way".
A similar results follows for "did it (in) the easy way"; "in" is not found.
This remains true for the following verb forms.
made: made it the easy,made it in the easy
do: do it the easy,do it in the easy
These results show that for most verbs, at least, the preposition is not used; it will even sound unnatural; however, it can still be used.
Instances of its use can be found in the past century and still today.
This dropping of the preposition applies more generally. Here is what can be read in CoGEL.
(CoGEL § 17.20) With expressions of manner and reason […] there is no preposition :
• That's the way (that) he did it. ['That's how he did it.']
• Is this the reason (that) they came? ['Is this why they came?']
In more formal style, we might find […] :
• That's the way in which he did it.
(CoGEL § 8.79) Noun phrases with way, manner, and style as head tend to have the definite article:
• She cooks chicken the way I like.
• She cooks chicken in the way I like.
• She cooks chicken in a way I like.
This shows that you can use constructions on the model of the following.
- Do it the hard way.
- Do it the other way.
- Do it the same way.
- Do it any way you want to.
However, for instance, people still use a lot "in the same way" (ngram, examples-prep., examples-no prep.), which seems to have regained some popularity recently.