Maven Shade plugin , main class not found (Scala, Intellij)

Question

I tried to look around a lot to solve this problem but I can't really solve it. In my scala project i'm trying to build a fatjar with all the dependencies in it, so here is my pom:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <version>2.3</version>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>shade</goal>
            </goals>
            <configuration>
                <transformers>
                    <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                        <mainClass>com.my.project.start.CommandStarter</mainClass>
                    </transformer>
                </transformers>
            </configuration>
        </execution>
    </executions> 
</plugin>

So i'm pointing to my main class, and in the manifest , inside the jar , i can see that the main class is there too..

But when i run my jar by launching : scala myjar.jar i have a

java.lang.ClassNotFoundException

Any suggestion?

Thank you!