In a standing mixer fitted with a paddle attachment, cream the butter and sugar, then add the eggs one at a time. Scrape the bowl down and mix on low until homogenous.
Add the sifted flour, sifted corn starch and salt in and mix on low for several minutes until the dough forms a ball and clings to the paddle.
Divide the dough into two batches and roll out between two pieces of parchment paper to a thickness of about 1/4 an inch. Place in the freezer to chill for about 30 minutes or so then cut your shapes out. Place on a parchment paper or silpat-lined baking sheet and chill again for about 10 minutes.
Bake on parchment paper for 5 minutes, rotate the tray and bake additional 3-6 minutes depending on the size, thickness and desired crispness.
Melt and cool white chocolate. Dip cookies halfway.