The trick to making a good fruit curd, custard or pudding (if eggs are used) is to temper those eggs before blending them with the hot mix on the stove. Oh -- and also use a double boiler, even if it's a glass bowl on top of a pot of simmering water.
To temper the eggs, whisk them in a separate bowl. Get about a teaspoon of the hot mixture and while still whisking, add the hot mix into the eggs. This gently warms them.
Then, start whisking the mixture in the pot and add the eggs slowly until they are incorporated, whisking vigorously the whole time. This will help the eggs keep from getting scrambled.