I've been using this salted caramel recipe:

SALTED CARAMEL CUPCAKES
MAKES 12 CUPCAKES
1 1/4 cups all-purpose flour
3/4 tsp baking powder
1/4 tsp salt
1 cup firmly packed dark brown sugar
1/2 cup granulated sugar
1/2 cup (1 stick) unsalted butter, at room temperature
2 large eggs, at room temperature
1 tsp vanilla extract
1/2 cup whole milk

Bake 350 for 18-20 minutes

http://www.howtoeatacupcake.net/2008/07/salted-caramel-cupcakes-finally.html

I love the taste of it and it gets rave reviews, BUT it is such a temperamental recipe. They remain flat and easily bubble over the sides. If I fill the liners with less batter, then they don't rise enough. It's like there's no happy-medium and I have experimented with this recipe a lot. Just last night I made these cupcakes and had to remake them, and I've used the recipe multiple times.

Any ideas?

I have a recipe like that. It is so temperamental. I'm an experienced baker, and this was the only recipe. I even measured the amount of space to leave when filling and the next time it would be wrong. I won't make it anymore and that is my best advice to you. There are many recipes for salted caramel cupcakes. Just move on. If you like some of the aspects and you are ok with changing recipes, take what you like about it and look for another similar recipe.

I did find another similar one that I'm going to try. Thanks!

There doesn't appear to be enough baking powder. General rule is 1 tsp per cup of flour. I'd use 1 1/4 tsp the next time you attempt it.