Combine water, cream of tartar, sugar and corn syrup in a sauce pan. Boil until 340` with a candy thermometer, or until a deep golden brown.
Remove from heat. Quickly stir in cinnamon, then butter, almonds, and finally baking soda.
Pour onto a Silpat mat, or onto an oiled parchment lined sheet pan and quickly spread out using a heat proof spatula. Cool completely and break into irregular pieces to serve.