Click on the recipe book next to Broosha and scribe Makin Stuf Da Grobb Way which gets placed in your inventory. This only needs to be done the first time you do one of the Goodies for Grobb quests, as you will get all of the recipes needed.
Collect the material you will need in Grobb, specifically:
15 Grobb shellfish, which can be found next to the ponds in the swamp near Grobb, e.g. ( -31, -81, -507 ) /waypoint -31, -81, -507 or ( -81, -87, -426 ) /waypoint -81, -87, -426.
15 congealed goo, which can be collected from slimy slugs found in a conduit around ( -444, -72, -964 ) /waypoint -444, -72, -964.