In a medium, heavy-bottomed pot over medium heat, combine granulated sugar, brown sugar, evaporated milk, and butter. Stir continuously to dissolve sugars.

Increase heat slightly to bring the mixture to a gentle boil, stirring until it reaches 240°F.

Remove pot from heat and let the mixture rest for about 5 minutes to cool slightly.

Stir in vanilla extract and toasted pecan halves until well coated.

Vigorously beat the mixture with a wooden spoon for about 3-5 minutes until it thickens.

Drop spoonfuls of the mixture onto a parchment-lined baking tray, shaping them as you go.

Allow the pralines to cool at room temperature for at least 30 minutes until hardened.

If desired, melt candy melts and drizzle over the cooled pralines for decoration.