Public Transport to Mama Bazooka

From Amsterdam:

Take a train from Amsterdam Central Station to Amersfoort Central Station.
From Amersfoort Central, take bus 76 towards Bunschoten-Spakenburg.
After about 15 minutes, get off at the stop "Haarbrug-Noord."
From there, it's just a 3-minute walk to Mama Bazooka! 

If you would like a more detailed planning and/or if you travel from a different place in the Netherlands check this website.