Kahlua Raspberry Parfait

3 (10 ounce) packages frozen sweetened raspberries
3/4 cup granulated sugar
1/2 cup Kahlua
2 tablespoons fresh lemon juice
2 tablespoons cornstarch dissolved in 3 tablespoons Kahlua
Whipped cream

Puree raspberries and strain to remove seeds. Add sugar, Kahlua and lemon juice to the puree. Bring to a boil over medium-high heat and whisk in cornstarch mixture. Cook until sauce thickens and runs clear, about 1 to 3 minutes. Remove from heat and cool. Cover and chill.

Makes 4 cups sauce.

For each parfait, layer vanilla ice cream with chilled sauce (and, when available, fresh raspberries). Finish with whipped cream and more berries.