For Ice Cream: Combine cream and milk in medium saucepan. Whisk in combined sugar, dextrose, dry milk and stabilizer. Heat on medium heat until mixture reaches 165°F.
Blend mixture, in small batches, in blender 30 seconds. Pour into medium bowl. Chill over ice bath until mixture is cold. Refrigerate overnight. Freeze mixture according to manufacturer's directions. When firm, stir in TOBLERONE Mini Chunks. Keep frozen until ready to use.
For Chocolate Cookie Dough: Line half sheet pan with parchment paper. Attach half sheet pan frame on top of parchment paper.
Melt chocolate and butter over warm water bath, stirring often. Do not heat above 100°F. Chocolate will firm up but should be able to mix into egg/sugar mixture.
Beat sugar, eggs and vanilla in bowl of mixer fitted with paddle attachment until well blended. Add chocolate mixture; mix on medium speed until combined. Scrape side of bowl and mix a few additional minutes. Add combined flour, baking powder and salt all at once. Mix until combined, scraping side of bowl as needed. Stir in TOBLERONE just until combined. Spread dough evenly in prepared pan. Chill pan while preparing second cookie dough.
For Cookie Dough: Cream butter, sugars and vanilla in bowl of mixer fitted with paddle attachment until well blended, scraping bowl as needed. (Do not overmix or dough will rise unevenly.) Add eggs, 1 at a time, mixing until blended after each addition. Add combined flour, baking powder and soda, and salt all at once. Mix until blended. Stir in 8 oz. TOBLERONE just until combined. Spread dough evenly over chilled chocolate dough in pan.
Bake in 325°F standard oven 50 to 60 minutes or until center is set. Rotate pan halfway through baking, lightly pushing down sides with a spatula if they have risen more than the center. Cool completely in pan on wire rack. Cut 4 x 8 into 32 pieces, with the 4 cuts being on the long edge of pan.
For Each Serving: Place one cookie bar on serving plate. Top with #30 scoop (1.25 oz.) Ice Cream, 1/4 oz. of the remaining TOBLERONE and 1 tsp. nuts.