In a bowl, mix together flour, oats, brown sugar, baking soda and salt together. Add in melted butter and mix until completely combined. Press half the mixture into the bottom of a greased 8 x 8" pan.
Bake for 10 minutes.
While baking, mix together heavy cream and soft caramels in a medium saucepan over low heat. Stir it for about 5 minutes (or until smooth), and then remove from heat.
Remove the pan from the oven, and pour melted caramel over top.
Top the caramel with chocolate chips and walnuts.
Crumble the remaining oat mixture over the top of the caramel.
Return to the oven for 12-15 minutes, or until the bars start to turn a golden brown.
Serve warm (they'll be gooey and delicious) or you can also refrigerate them.