Place softened ice cream in large bowl. Fold in 2 cups cherries. Cover with plastic wrap; freeze 30 minutes.

Combine remaining 4 cups cherries, sugar, ⅓ cup water and vanilla in a medium saucepan. Bring to a boil; reduce heat to medium-low heat. Simmer 6 to 8 minutes until cherries soften.

Stir together remaining 1 tablespoon water and corn starch in a small bowl until well combined; stir into cherry mixture. Continue cooking 3 to 5 minutes or until sauce thickens, stirring occasionally. Remove from heat; cool.

To assemble, layer cherry sauce, cherry ice cream and brownie cubes in 6 (8-oz.) glasses. Garnish with additional cherries, if desired. Serve immediately.