Grease the slow cooker: Lightly coat a 5–6 quart crockpot with nonstick spray or a thin layer of butter to prevent sticking.
Layer the cherries: Spread both cans of cherry pie filling evenly over the bottom of the crock.
Add vanilla and salt: Drizzle the vanilla over the cherries and sprinkle on a small pinch of salt. Gently swirl with a spoon.
Top with dry cake mix: Sprinkle the chocolate cake mix evenly over the cherries.
Do not stir.
Add chocolate chips: Scatter the chocolate chips over the dry cake mix.
Pour on melted butter: Slowly drizzle the melted butter across the entire surface so most of the dry mix is moistened. A few dry spots are fine.
Cook: Cover and cook on High for 2 to 2.5 hours or on Low for 4 hours, until the top looks set and the edges are bubbling. The center will be soft and pudding-like.
Rest: Turn off the heat and let it sit, covered, for 10–15 minutes.
This helps it thicken slightly for cleaner scooping.
Serve: Spoon warm portions into bowls and top with ice cream or whipped cream.