Preheat oven to 450 degrees. Grease a cookie sheet.

In a medium saucepan, combine 1/2 cup butter and 1 cup water. Bring to a boil, stirring until butter melts completely. Reduce heat to low, and add flour and salt. Stir vigorously until mixture leaves the sides of the pan and begins to form a stiff ball. Remove from heat. Add eggs 1 at a time, beating well to incorporate completely after each addition. With a spoon or a pastry bag fitted with a #10 or larger tip, spoon or pipe dough onto cookie sheet in 1 1/2 x 4in strips.

Bake 15 minutes in the preheated oven, then reduce to 325 degrees and bake 20 mins more, until hollow sounding when lightly tapped on the bottom. Cool completely on a wire rack.

For the filling combine pudding mix and milk in a medium bowl according to package directions. In separate bowl, beat the cream with an electric mixer until soft peaks form. Beat in 1/4 cup confectioner's sugar and 1 teaspoon vanilla. Fold whipped cream, into pudding. Cut tops off of cooled pastry shells with a sharp knife. Fill shells with pudding mixture and replace tops.

For the icing, melt the chocolate and 2 tablespoons butter in a medium saucepan over low heat. Stir in 1 cup confectioner's sugar and 1 teaspoon vanilla. Stir in hot water, one tablespoon at a time, until icing is smooth and has reached desired consistency. Remove from heat, cool slightly, and drizzle over filled eclairs.

Refrigerate until serving.