Preheat oven 350°
Line an 8 inch square pan with foil. Grease foil and sides of pan.
In a large mixing bowl, combine the eggs and sugar. Using an electric mixer, beat until creamy. Add vanilla extract and mix, then add the flour and salt. Beat until mixture is crumbly.
Spread the shortbread onto the grease pan evenly. Press firmly to flatten mixture. Bake on the middle rack in the oven for 20 minutes or until it’s a light golden color. Remove from oven and allow to cool on a wire rack.
Using a saucepan on a medium-high heat, pour the sweetened condensed milk and stir continently. When you begin to see brown streaks in the pan turn the heat down to a simmer. Stir until you have a smooth caramel color.
Pour your caramel onto the shortbread and spread evenly. Place in the refrigerator for 30 mins.
Make a double boiler using a glass/ metal bowl over a saucepan of water. Melt the chocolate and canna-butter together, mixing well. Pour over the caramel again and spread evenly. Once again, place in the refrigerator for 15 minutes. Cut into pieces with a sharp knife. Serve chilled or at room temperature.
Will keep fresh one week stored in refrigerator.