Here is a suggestion for you: use a hash of arrays to store your information. You can key the hash off the main recipe name ('sandwich', 'eggsalad') easily enough:

#!/usr/bin/perl 
 
use strict; 
 
my $file='mydata.txt'; 
my %hash; 
 
open IN,$file || die $!; 
 
my $key; 
 
while (<IN>) { 
  ## remove the end-o-line 
  chomp; 
  ## blank line means a new recipe 
  if (/^\s*$/) { 
    undef $key; 
    next; 
  } 
  ## stuff the key with something 
  if (! defined $key) { 
    $key=$_; 
    next; 
  } 
  ## okay, split the line and add the parts 
  push @{$hash{$key}},split /\s{2,}/,$_; 
} 
 
close IN; 
 
for my $key (sort keys %hash) { 
  print "'$key' is made with: ".join(",",@{$hash{$key}})."\n"; 
}
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Now, the only problem with this is that the ingredients have to be seperated with more than one space (as with your example).