To generate a shopping-list for the recipes I want to cook.

food-shopping-list.el

(defun flush-blank-lines ()
    "Removes all blank lines from buffer or region"
     (interactive)
     (save-excursion
       (let (min max)
         (if (equal (region-active-p) nil)
             (mark-whole-buffer))
         (setq min (region-beginning) max (region-end))
         (flush-lines "^ *$" min max t))))
  
  (defun food/gen-shopping-list ()
    (interactive)
    (goto-line 0)
    (let ((start-shopping-list (search-forward "* Einkaufsliste" nil t)))
      (while (search-forward "** TOCOOK" nil t)
        (show-subtree)
        (outline-next-visible-heading 1)
        (next-line)
        (let ((start (point)))
          (outline-next-visible-heading 1)
          ;;(previous-line)
          (copy-region-as-kill start (point)))
        (save-excursion
          (goto-char start-shopping-list)
          (newline)
          (yank)
          (show-subtree)
          (delete-blank-lines)))
      (goto-char start-shopping-list)
      (org-mark-subtree)
      (next-line)
      (flush-blank-lines))
    (org-table-align)
    (previous-line)
    (org-shifttab))
  
  
  (defun food/clear-shopping-list ()
    (interactive)
    (save-excursion
      (goto-line 0)
      (let ((start-shopping-list (search-forward "* Einkaufsliste" nil t)))
        (show-subtree)
        (outline-next-visible-heading 1)
        (previous-line)
        (end-of-line)
        (kill-region start-shopping-list (point)))))