This is a traditional fudge, a long cooking time and yes, you have to keep an eye on it. It is very dense and very rich. Do eat it soon after making and keep leftovers tightly wrapped.
- 2/3 cup canned evaporated milk
- 1 1/2 cups brown sugar, packed
- 1/2 cup + 2 Tbsp unsalted butter (1 1/4 sticks)
- 1/4 tsp kosher salt
- 1/2 cup powdered sugar
- 1 tsp pure vanilla extract
- 1 cup diced walnuts (3 ounces)
Line an 8×8″ glass baking dish with plastic wrap, allowing extra to lay over the sides (laying one piece down, then another piece the other direction works well, giving “handles”).
Bring the milk, brown sugar, butter and salt to a boil in a tall and heavy saucepan, stirring constantly with a silicone spatula or a wood spoon. Turn to medium-low, set the timer for 25 minutes and let bubble. Clip in a candy thermometer and watch for 236° (which is about 25 minutes). Stir often during the cooking time.
Take off the stove and scrape into a large heat proof mixing bowl, add in the powdered sugar and beat on low-speed with a hand mixer for 1 minute. Turn up to medium and beat for 2 minutes. Turn back to low and add in the vanilla and walnuts.
Scrape the fudge into the prepared dish and pat down. Use a small piece of plastic wrap to flatten and smooth it out. Score the fudge and cut into 18 to 24 pieces. Let cool on the counter for a couple hours.