Ok, fixed it.
I was looking the wrong way.
Visual Studio create a web.config file in Views folder having the following line:
<add name="BlockViewHandler" path="*" verb="*" preCondition="integratedMode" type="System.Web.HttpNotFoundHandler" />
which I just had to change to
<add name="BlockViewHandler" path="*.cshtml" verb="*" preCondition="integratedMode" type="System.Web.HttpNotFoundHandler" />