Given that Scala runs on the Java Virtual Machine (JVM), you can use the JVM tools JConsole and VisualVM to profile the application. Alternatively any Java profiler should work (e.g. YourKit, as you’ve already mentioned)
VisualVM has been bundled with the JDK since 1.6.0_10 and it is based on the NetBeans profiler. You can capture memory usage, code performance hotspots etc:
C:> %JAVA_HOME%\bin\jvisualvm