Recursive Topological sort implemented (Presumably).

src/RecipeTree.java

@@ -1,3 +1,5 @@
+import java.util.Stack;
+
 public class RecipeTree
 
 {
@@ -62,4 +64,19 @@ public class RecipeTree
             root.printNode();
         }
     }
+
+    public Stack<RecipeNode> sortTopologically(RecipeNode currentNode) {
+        Stack<RecipeNode> recipeStack = new Stack<>();
+
+        if(currentNode.getChildren() == null) {
+            recipeStack.push(currentNode);
+            return recipeStack;
+        } else {
+            for (RecipeNode childNode : currentNode.children) {
+                recipeStack.push(currentNode);
+                sortTopologically(childNode);
+            }
+        }
+        return recipeStack;
+    }
 }