Here's a recipe that I make in an 8" square pan, but it is not very similar:

Cherry Cream Crunch

Cherry
pie filling:*

2
tbsp fresh lemon juice
1/2
cup sugar
2
cups fresh pitted cherries
2
tablespoons cornstarch

Crust:

1/2
cup unsalted butter
1/3
cup brown sugar
1
tsp vanilla
1
cup sifted all purpose flour
1/4
tsp salt
1/2
tsp cinnamon
1
cup flaked or shredded coconut, unsweetened
1
cup granola (or oatmeal or rice flakes**)
1/2
cup chopped walnuts

Lemon
filling:

2
eggs, slightly beaten
1
can (15 oz.) sweetened condensed milk
1
tbsp grated lemon rind
1/4
cup fresh lemon juice

Combine
sugar and lemon juice in a bowl,
stir, add cherries, and let sit for at least 6 hours, stirring
occasionally. Drain off and reserve cherry syrup.

Combine
a small amount of syrup to cornstarch to make a paste, then stir
cornstarch
paste back into syrup. Pour mixture into a saucepan and cook over
medium heat, stirring, until the sauce thickens. Stir in the drained
cherries. Cool before using.

Crust:

Cream
butter in a large mixing bowl; gradually add brown sugar and vanilla.
Mix well. Sift flour, salt and cinnamon; add to butter mixture. Stir
in coconut, granola, and walnuts. Press 2-1/2 cups of crumb mixture
into bottom of ungreased 9x13 inch baking dish. Bake at 375 degrees
for 12 minutes.

Lemon
filling:

Prepare
the lemon filling by combining the slightly beaten eggs, sweetened
condensed milk, grated lemon rind, and fresh lemon juice. Stir
until mixture thickens. Remove crust from the oven and spread with
lemon filling. Spoon the cherry pie filling over the lemon filling
and then sprinkle with the remaining crumb mixture. Return to oven
and bake at 375 degrees 15 to 18 minutes or until delicately browned.
Chill before serving. May be served topped with whipped cream. Serves
9 to 12.

*You
can substitute 1 can (1 lb 4 oz.) of canned cherry pie filling

**If
using oatmeal or rice flakes instead of granola, increase brown sugar
to 1/2 cup.

I adapted this recipe from Orowheat Bakery's cookbook, Cooking with Gourmet Grains from the 1970s.

Crispy corners are not a bad thing and neither is a moist center. Do the toothpick test and see how it does. I think it would be fine in a square pan.

Thanks Peppi....wondering if I need to make a test run or just go for it.
I guess caramel sauce and ice-cream cover a lot of dried out and too moist!

Try four small bits of loose tented foil over those corners covering the 4 'triangle' edges. Might be just enough heat protection like i do with some pie crusts.

Good idea...I also do that sometimes for a pie....never thought for a square cake.

I've made it in the mini foil pie pans and the round foil cake pans for the bake sales at the church and have had no problems at all.