Prepare Pan:
Grease and line a 9”x13” pan (or smaller for thicker pieces). Set aside.

Melt Sugar Mixture:
In a large microwave-safe bowl, combine sugar, milk, and butter. Heat in 30-second intervals, stirring each time, until butter melts and sugar begins dissolving.

Boil:
Transfer mixture to a deep stockpot or large saucepan. Bring to a boil over medium-high heat, stirring occasionally.

Add Condensed Milk:
Once sugar has dissolved, pour in condensed milk and reduce heat to medium. The mixture will expand, so ensure your pan is deep.

Simmer:
Let mixture gently bubble for 15–20 minutes, stirring frequently to prevent burning. The mixture will thicken and turn caramel-colored.

Check Temperature:
It should reach 240–248°F on a candy thermometer (soft-ball stage). Alternatively, drop a small amount into cold water — if it forms a soft ball, it’s ready.

Flavor (Optional):
Remove from heat and stir in vanilla extract or whiskey if desired.

Beat Mixture:
Using a hand mixer, beat for 8–10 minutes until thickened and matte. (Or stir vigorously with a wooden spoon until trails form.)

Set:
Pour into prepared pan without smoothing the top too much. Tap gently to spread evenly.

Score & Cool:
After 10 minutes, score the surface into squares. Let set 2–4 hours (or overnight), then cut completely along scored lines.