This recipe is adapted from Allrecipes.com. I had to increase the amount of cornstarch and am not sure exactly how much I ended up using. You may need to add a little more to get your filling to thicken. Just remember it will thicken a little more in the oven as it's baking. I think I ended up thickening it a bit too much becasue it was very thick when I took it out of the oven...it was still super tasty nonetheless!
4 C sour cherries, pitted
2 C sugar
4 Tbsp Cornstarch
2 Tbsp butter
1/4 tsp almond or vanilla extract
2 pie crusts
Place cherries, sugar and cornstarch in medium, a non-aluminum pan. Stir and let sit for 10 minutes. Bring to a boil over medium heat; stirring constantly. Lower the heat and simmer until the juices have thickened and become transluscent- about 2-3 minutes. Remove from heat and stir in butter and extract of choice. Pour into pie shell and bake in preheated 375 degree oven 45-50 minutes or until cust is golden brown.