Preheat oven to 350°F. Line pan with parchment.
Whisk butter and sugar. Add eggs one at a time.
Combine flour, cocoa, salt; add to wet mixture.
Stir in vanilla + chocolate chips; spread batter.
Bake 25–30 mins; cool completely.
Cook cherries, sugar, cornstarch, lemon until thick.
Let cherry mixture cool. Spread over base.
Refrigerate 2+ hours.
Whip cream, sugar, vanilla until soft peaks.
Spread cream over cherries; garnish with chocolate.
Cut into squares and serve chilled.