I've never heard of cooking butter to a precise temperature.  Your recipe is wrong (as most written recipes are).

The hardness of your caramel has entirely to do with the temperature to which you cook the sugar syrup BEFORE you whip in any butter or egg whites.  Working with boiled sugar is not immediately easy to do.  There are chefs who study for years on working with sugar

Sugar Stages:
Thread  230f
Soft Ball  240F
Firm Ball 245F
Hard Ball 255
Small Crack 265
Crack  275
Hard crack 300
Caramel 320

Don't ever listen to a recipe that tells you to do things by time or sight.  A thermometer is the ONLY way to work with sugar syrup.  The recipe tells you to cook until it's amber color.  This starts happening at 320F, way past the soft ball stage you need for a caramel topping for a tart.  So, sight won't do.  I'd suggest cooking the sugar to 245F precisely. 

Without a thermometer, you can add a few drops of your syrup to cold water and see what results.  If the sugar turns into a soft ball (like gummy candy), it's about 240F.  If the dripped sugar turns into a hard piece of candy, you've gone too far.

More tips:  Add a very small pinch of cream of tartar or a tiny drop of lemon juice to inhibit chrystalization in the sugar.  When you are boiling the sugar, use as little water as possible.  The goal is to evaporate all the water from the dissolved sugar.  The more water you start with, the longer it will take.  As the syrup boils, wash the sides of the pan down with a pastry brush and cold water to keep the sugar from drying on the side of the pan.  If it drys and turns to chrystals, it will begin a chain reaction and make all your syrup crunchy.

Written recipes don't teach you to cook any more than having sheet music teaches you to play piano.  A good understanding of the basic cooking methods behind them will make any recipe better, or empower you to create your own.

I like your opinion. thanks

I agree with chef todd. Thanks for listing the stages and temperatures each on happens at.

This always happens to me! lol! Good reply above though - It will certainly help. Thanks for sharing!

Quote:


You are right Chef Todd, that is the reason why I prefer to read online recipes (esp. from forums like this one), and today it looks like I have found an even better place to learn culinary skills from.

Ingredients

    * 3 cups white sugar
    * 1 1/2 cups corn syrup
    * 1 pinch salt
    * 2 cups liquid non-dairy creamer
    * 1/2 teaspoon vanilla extract

Directions

   1. In a heavy bottomed saucepan, combine sugar, corn syrup, salt and 1 cup non-dairy creamer. Heat to between 234 and 240 degrees F (112 to 116 degrees C), or until a small amount of syrup dropped into cold water forms a soft ball that flattens when removed from the water and placed on a flat surface.
   2. Combine vanilla and remaining creamer and stir, a little at a time, into caramel. For a soft caramel, remove from heat and pour into a buttered 8x8 inch dish. For a hard candy or caramel apple coating, continue cooking until mixture reaches hard ball stage, 250 to 265 degrees F (121 to 129 degrees C), or until a small amount of syrup dropped into cold water forms a rigid ball.

Chef todd is right you need thermometer to see wich temperature you need to cook at. This way you can try a few different ones to see wich one works best for you.

try the recipe i just posted