Is there a term for a recipe inside a recipe?
You can remove the quotation marks from "sub-recipe," because that's the correct term, at least in recipes and recipe books. I haven't found a dictionary definition; however, subrecipe and parent recipe are terms used in other fields as well.
subrecipe/sub-recipe
What is a sub-recipe?
Keywords: subrecipe, sub-recipeA sub-recipe is a recipe that is used as a component in a parent recipe.
Sub-recipes are used to simplify the parent recipe by breaking the recipe up into smaller recipes that reflect their production (e.g., a sub-recipe tomato sauce gets prepared before assembling a pasta dish).
I've included ten recipes for homemade mixers in the subrecipe section of this book... Jim Meehan; Meehan's Bartender Manual.
See the subrecipe for Pizza Dough. ref.
The recipe for Miso Soup with Tofu, Shiitakes, Noodles, and Baby Spinach (page 64) includes a subrecipe for homemade dashi. Catherine Jones et al.; The Calories In Calories Out Cookbook.
They also indicate clearly when the time to make a subrecipe, such as a crust or frosting, is not included in the overall time. You'll will need to remember to factor in the time to make those subrecipes. Carolyn Ketchum; The Ultimate Guide to Keto baking.
Both sub-recipe and preparation are things that you make in bulk, in house. This can be pizza dough, tomato sauce, slices of tomatoes, or even kits of napkin-fork-knife. Jordan Silverman; 'Preparations and Sub-Recipes'.