Recipes allow you to combine multiple ingredients into a single serving, with nutrition information automatically portioned, which you can log on your daily log as a single entry.
You can create a recipe by tapping the + button in the bottom navigation or the + button in the top right corner of the food search screen, then:
Tap "Create Recipe"
Enter the Recipe name
Enter the number of servings
Add your ingredients
Fun fact: Ingredients can be automatically portioned according to your nutrition goal for that food, just like foods logged to a meal. For example, if you wanted your recipe to contain 100 g of protein from chicken breast, then add chicken breast as an ingredient, enter 100 in the protein field, and observe the ingredient quantity update to provide 100 g of protein. 
To delete an ingredient from the recipe, swipe it to the left.
Enter the total weight of the whole recipe after cooking (optional but awesome)
This allows you to portion the recipe using additional serving units, such as ounces, grams, cups, or other units, instead of relying only on servings. For example, if a soup yields five servings, estimating one-fifth each time can be imprecise. If the cooked recipe weighs 1,500 grams and you enter that total, you can log portions by weight or volume in addition to servings for more accurate tracking.
Add preparation instructions by tapping the + button next to Preparation.
Tap the done checkmark in the top right corner to create your recipe.
From the food search, tap the Recipes tab
Tap on the recipe you wish to edit
If you're in a food logging flow, tap the ... button in the top right corner and select Edit Recipe
If you entered from More > Saved Foods, Meals & Recipes, then you can make your edits on this screen
Make your edits
Tap the done checkmark in the top right corner to save your recipe edits.
Copying a recipe is helpful to create different versions of a recipe without having to start from scratch each time.
From the food search, tap the Recipes tab
Tap on the recipe you wish to copy
Tap the ... button in the top right corner and select Create Copy
Make any edits on the Create Recipe screen and tap the checkmark in the top right corner when done
If you're in a food logging workflow, then on the Add Recipe screen, set your serving size and tap the checkmark in the top right corner to log your new recipe to your meal