Summarize the following:
If you know that you want a thick caramel sauce, cut down on the amount of milk that the recipe suggests. Leave out about 1/3 or 1/2 of the recommended milk. This will result in a caramel sauce that's thicker and that you won't have to spend extra time simmering. For example, if a recipe calls for 1.5 cups (360 mL) of milk, try only using 1 cup (250 mL). Most caramel sauces are made by caramelizing sugar and adding milk and a little salt. If you increase the amount of sugar in the recipe you'll end up with a thicker caramel. Try increasing the sugar by about 1/3. The amount of milk suggested by the recipe, then, will leave you with a thick caramel sauce. Be aware that this will also increase the sweet, caramel flavor of the sauce. If you want a caramel sauce with a milder flavor, avoid adding the extra sugar. If you want a thick caramel sauce but would rather avoid altering the amounts of ingredients given in a recipe, you can simply use heavy whipping cream instead of milk. The whipping cream will taste the same as milk in the final product, but will produce a thicker sauce. Switching out milk for cream will result in a rich, heavy caramel sauce.
Reduce the amount of milk. Add more sugar to the sauce. Substitute cream for the milk.