In schema.graphql:

type Mutation {
  ...
  createRecipe(
    name: String!
    ingredients: [IngredientInput!]!
    instructions: [String!]!
    categories: [CategoryInput!]!
  ): Recipe
}

And the mutation in resolves (index.js):

createRecipe: (_, args, context, info) => {
      return context.prisma.mutation.createRecipe(
        {
          data: {
            name: args.name,
            ingredients: args.ingredients,
            instructions: args.instructions,
            categories: args.categories
          }
        },
        info
      );
    }