Prep your pan: Lightly grease and line a 9×13-inch baking dish with parchment paper. You can use a smaller dish if you prefer thicker pieces.

Start the mixture: In a large microwave-safe bowl, combine the sugar, whole milk, and butter. Heat in 30-second intervals, stirring between each round, until the butter is melted and the sugar begins to dissolve.

Cook the base: Pour the warm mixture into a deep stockpot or large saucepan. Turn the heat to medium-high and bring to a boil, stirring occasionally. Once the sugar has dissolved completely, stir in the sweetened condensed milk.

Simmer with care: Reduce heat to medium and allow the mixture to simmer gently for 15–20 minutes, stirring frequently to prevent sticking or burning. The mixture will rise as it cooks — so make sure your pot is deep enough.

Check for doneness: When the mixture becomes thick and golden caramel in color, it’s time to test the temperature. It should read 240–248°F (soft ball stage) on a candy thermometer. Or, drop a bit into cold water — if it forms a soft ball, it’s ready to remove from heat.

Add flavor (optional): After removing from heat, stir in vanilla extract or whiskey for a flavor twist.

Beat for texture: Using a hand mixer, beat the mixture for 8–10 minutes until it begins to thicken and leaves visible trails as you mix. (You can also use a wooden spoon, though it’ll take a bit longer.) This step gives the tablet its signature grainy-fudgy texture.

Pour and set: Quickly pour the thickened mixture into your prepared pan. Avoid spreading the surface with a spoon — just tap the pan gently on your countertop to help it settle evenly.

Score and slice: After 10 minutes, score the top with a sharp knife to make cutting easier later. Let it set at room temperature for 2–4 hours, or overnight, until completely firm. Once set, cut into squares or rectangles.