These turtles are topped with caramel and chocolate for a truly delightful candy that's perfect for gifting.
Preheat oven to 350 degrees. Toast nuts on a baking pan for 10 minutes; remove from oven. Generously butter 5 baking pans. Arrange 5 pecan halves in a snowflake-shaped cluster, overlapping nuts in center. Repeat with remaining nuts, spacing clusters 2 inches apart.
In a heavy saucepan, combine corn syrup, whole milk, and sugar. Place over medium-high heat; cook, stirring occasionally with a wooden spoon, until syrup mixture comes to a boil, about 6 minutes. Stir in baking soda. Clip a candy thermometer to pan; add butter, stirring constantly until melted, keeping mixture at full boil. Slowly pour in evaporated milk; cook at a boil, stirring constantly, until temperature reaches 240 degrees (soft-ball stage), about 45 minutes. If pan starts to overflow, turn down heat for a few minutes; return to a boil.
Remove caramel from heat; transfer to a medium metal bowl. Cool to 200 degrees. Caramel will have the consistency of thick honey.
Using a spoon, gently mound 1 tablespoon caramel on top of each cluster. Allow caramel to harden. If caramel becomes too stiff, place bowl over low heat; stir constantly for several minutes until returned to proper consistency.
To temper chocolate, cover a heating pad with a kitchen towel, and set pad to lowest setting. Line two baking pans with parchment paper, and set aside. Using a sharp knife, shave chocolate.
In a medium glass bowl, heat two-thirds of the chocolate in microwave at 30 percent power for 1 minute. Stir chocolate, and continue heating at 30 percent power in 10-second intervals until an instant-read thermometer registers 120 degrees. Remove from microwave.
Stir in remaining shaved chocolate with rubber spatula. Stir constantly, bringing chocolate up sides and back down into bowl until temperature reaches between 86 degrees and 89 degrees. To determine if tempered, drizzle a thin line onto a cool stainless-steel surface. The chocolate should dry to a matte finish in about 5 minutes. Place bowl on covered heating pad; stir occasionally to maintain temperature between 86 degrees and 89 degrees adjusting setting if necessary.
Drizzle 1 tablespoon of tempered chocolate over each cluster; set aside in a cool place to harden.
If you don't want to temper chocolate, cover the nut clusters in melted chocolate and freeze them. Then serve directly from the freezer.