Most things in Meal Garden (a Recipe Collection, a recipe from your Cookbook, a scheduled recipe in a meal plan, etc.) can be deleted by clicking and dragging them toward the bottom of the screen where a garbage can will appear. 

Drop the item into the bin.

Examples:

Deleting a Recipe Collection:

Deleting a Recipe from your Cookbook:

Deleting a Recipe from a Meal Plan:

Did this answer your question?