Step 1

To make ice block, fill bundt pan with water and freeze until solid, about 8 hours.

Step 2

Stir together sugar and 3 1/2 cups water in a large bowl or pot until sugar is dissolved. Add lemon juice, rum, Cognac, and brandy and chill, covered, at least 3 hours.

Step 3

Put ice block in a punch bowl. Top with lemon slices. Pour punch over top.