1. Combine first 3 ingredients in a medium saucepan. Bring to a simmer over medium-high heat. Reduce heat to medium and simmer 12 minutes or until cherries are tender. Remove pan from heat; stir in almond extract. Transfer cherry mixture to a bowl. Cool 10 minutes.
2. Place cherry mixture in a blender; add lemon juice, and process until smooth. Pour mixture through a sieve into a bowl, pressing with the back of a spoon to extract juice. Discard solids. Set bowl in a large ice-filled bowl until cold, stirring occasionally.
3. Pour mixture into a 13 x 9-inch glass or ceramic baking dish. Cover and freeze until partially frozen (about 1 hour). Scrape with a fork, crushing any lumps. Freeze, scraping with a fork every hour, an additional 3 hours and 30 minutes or until completely frozen.
4. Spoon granita into bowls; top evenly with almonds.