1. Roll out the puff pastry into three 8 inch squares. Place on a parchment lined cookie sheet. You may have to bake these one at a time depending on the size of your cookie sheet. Dock the pastry by stabbing holes in it with a fork about every half inch over the entire surface of the pastry. Chill it in the freezer for 10 minutes to ensure that it is well chilled. Puff pastry MUST be baked very cold. Place another sheet of parchment paper on top of the pastry and weight it down with another cookie sheet on top. This keeps the pastry from puffing too much and ensures that it is crispy when baked.
2. Bake in a preheated 425 degree oven for about 15 minutes. Decrease the heat to 375 degrees F, remove the top pan and top sheet of parchment paper and bake for about another 5 minutes or so until it is evenly medium golden brown throughout. Cool the baked pastry sheets completely before filling.

To prepare the Vanilla Buttercream Frosting

1. Blend all the ingredients together until smooth. Only add a little milk at the beginning, then add more if you need it. You want a very thick frosting here. It should still be easily spreadable but as thick as possible is best.

To construct the mille feuille

1. Take one quarter of the frosting and spread it evenly on one layer of the baked pastry. On top of the frosting, spread a thin layer of very good quality raspberry jam.
2. Spread another quarter of the frosting onto the next sheet of baked pastry and invert it on top of the raspberry jam so that the jam is sandwiched between two thin layers of frosting. This technique helps the completed pastry to hold together better.
3. Next, spread another quarter of the frosting amount onto the top of the inverted pastry layer, followed by another thin layer of raspberry jam. Finally spread the last of the frosting onto the last sheet of baked puff pastry and invert that onto the raspberry jam. Chill the constructed mille-feuille while you prepare the glaze for the top.

To prepare the Vanilla Glaze

1. Blend the icing sugar, vanilla and milk together well using only enough milk to bring the glaze to a very thick consistency. The glaze should be just at the point where it almost isn't pourable but still goes to a flat surface when you stop stirring, even if it takes a couple of seconds to do so. Spread the glaze evenly over the surface of the constructed mille-feuille.

To garnish the top with chocolate stripes.

1. Melt together the chocolate chips and butter.
2. Spoon the melted chocolate into a Ziploc bag and snip the corner off with scissors. The opening should be quite small, about the size of a pencil lead. Draw lines of chocolate all across the surface of the glaze, parallel to each other and about a half inch apart. Using the back of a knife or a toothpick, draw lines perpendicular to the chocolate lines across the surface of the glaze, about every inch, alternating the direction of the lines as you go.
3. Chill the completed mille-feuille for at least a couple of hours, preferably longer. Trim all four edges of the pastry so that you have straight sides before cutting into 8 rectangles or 16 squares. The trimmings are the bakers bonus...enjoy!