Trace variables
You already know the 
XML DSL
<testcase name="traceVariablesTest">
    <variables>
        <variable name="myVariable" value="12345"/>
        <variable name="nextVariable" value="54321"/>
    </variables>
    <actions>
        <trace-variables>
            <variable name="myVariable"/>
            <variable name="nextVariable"/>
        </trace-variables>
        <trace-variables/>
    </actions>
</testcase>
Java DSL designer and runner
@CitrusTest
public void traceTest() {
    variable("myVariable", "12345");
    variable("nextVariable", "54321");
    traceVariables("myVariable", "nextVariable");
    traceVariables();
}
Simply add the 
Current value of variable myVariable = 12345
Current value of variable nextVariable = 54321