Line an 8×8-inch (20×20 cm) square baking pan with parchment paper, letting it overhang on two opposite sides to create a sling. Lightly mist the parchment with nonstick spray if needed to help it stay in place and for easier removal later.
On a cutting board, chop the gumdrops or spice drops into small, pea-sized pieces. Place them in a bowl and toss with 1–2 teaspoons of cornstarch or powdered sugar just until lightly coated, then shake off any excess. This helps keep them from clumping together and sinking in the fudge.
1 1/2 cups gumdrops or spice drops, 1 teaspoon cornstarch or powdered sugar
In a medium saucepan, combine the white chocolate chips, sweetened condensed milk, and unsalted butter. Set over low heat and cook, stirring constantly with a heatproof spatula, until the mixture is fully melted, smooth, and glossy. If it begins to look grainy or like it’s seizing, remove from the heat and continue stirring; the residual heat in the pan will often finish melting it.
3 cups white chocolate chips, 14 oz sweetened condensed milk, 4 tablespoons unsalted butter
Remove the saucepan from the heat. Stir in the vanilla extract, almond extract (if using), and fine sea salt until fully combined. Taste a tiny amount carefully (it will be warm) to check that the flavor is sweet, creamy, and balanced.
1 teaspoon pure vanilla extract, 1/4 teaspoon fine sea salt, 1/4 teaspoon almond extract
Let the fudge mixture cool in the pan for about 3–4 minutes so it is no longer piping hot. Gently fold in about 1 1/4 cups of the chopped gumdrops, reserving a small handful for the top. Stir just enough to distribute them evenly without over-mixing, which can smear the colors.
1 1/2 cups gumdrops or spice drops
Pour the fudge mixture into the prepared 8×8-inch pan and smooth the top with a spatula. Press the remaining chopped gumdrops gently into the surface so they are visible on top. If using, sprinkle festive sprinkles over the top and gently press them in so they adhere.
1 1/2 cups gumdrops or spice drops, 2 tablespoons festive sprinkles
Transfer the pan to the refrigerator and chill for 2–3 hours, or until the fudge is firm. The center should feel set and not squishy when gently pressed. In a very full fridge or warm kitchen, it may take closer to 3 hours.
Use the parchment sling to lift the fudge out of the pan and onto a cutting board. With a sharp knife, trim the edges if desired, then cut into about 1-inch squares or rectangles. For cleaner cuts and less sticking on the gumdrops, wipe the knife with a warm, damp cloth between slices and rewarm as needed.