Go to Layout then EditHtml
Search for this tag <title><data:blog.pagetitle/></title>
Replace this tag with Following tag-
<b:if cond='data:blog.pageType == "index"'>
<title><data:blog.title/></title>
<b:else/>
<title><data:blog.pageName/></title>
</b:if>
I hope you will like this swap title hack as this is very good for search engine optimization.