Yes, on Sub-Recipes click Upload Subrecipes:

1. Click Download Template to get subrecipes.csv. Its columns are name, productioncost, costperhour, timetoprepare, baseweight and baseunit (the unit's ID).
2. Fill one row per sub-recipe, keep the header row, save as .csv.
3. Drag the file onto the upload area and click Import Subrecipes.

Every row creates a new, active sub-recipe (existing ones are not updated) with Auto Macros and Auto Cost switched off. You get a message like "Imported success 8 lines and 0 lines with errors!". This importer is separate from the meal importer on the Meal Recipes page and does not import plain ingredients, only sub-recipes.