This solution enables you to target a specific widget so all links generated by that widget, open in a new window. In this case, the code only applies to the genesis featured posts widget so both the entry title and featured image links open in a new window. All other links on the site open in the same window or however they are coded by default.
You can use this code with other widgets simply by changing the classes in the code to match the links in your widget or any other links you want to target and make open in a new tab.
Here’s the code for logged in members: