PSA: stop greasing your cake pans with butter, use this instead
Butter kept burning the edges of my layer cakes at 350 degrees, so I tried the pan release paste from a bakery supply place in Denver, equal parts shortening, oil, and flour. My cakes slid out clean 4 batches in a row, no parchment needed. Has anyone tried it on bundt pans with those tight crevices?
Used to think butter was the only way to go, mostly because my mom always did it that way, and her cakes were great. Then I had the same problem you did, burnt crusty edges and a center that stuck no matter how careful I was. Tried that same shortening, oil, and flour mix after a neighbor who bakes for our school bake sale swore by it. Four batches later I stopped buying parchment circles, and I am not going back. For bundt pans honestly the paste works even better than a spray because you can push it into the crevices with a pastry brush or even your fingers. Give it a shot, your mileage may vary on the ratio though, I go a little heavier on the flour for buntlets.