"Consuming" a Recipe refers to Crafting then eating 20 different Food Dishes over the Course of the Game. You may find a few Foods in chests around the game as well and there are Far more Food items and Recipes than this Achievement Requires.
It's likely you'll be getting this Achievement without thinking about it, as Mariam is given a Permanent Stat Boost anytime she Eats a food item for the First Time.