Stir in 2 teaspoons of strawberry extract, mixing thoroughly. Taste a small dab (careful, it will be warm) and add up to 1 more teaspoon of extract if you prefer a stronger strawberry flavor. Work quickly so the mixture stays pourable.
Immediately pour the fudge mixture into the prepared pan. Use an offset spatula or the back of a spoon to spread it into an even layer, smoothing the top as best you can.
Let the fudge cool at room temperature until it is no longer warm, then transfer the pan to the refrigerator. Chill for at least 2 hours, or until the fudge is firm enough to cut cleanly.
Once fully set, use the parchment overhang to lift the fudge slab out of the pan and onto a cutting board. Use a sharp knife to cut it into 16 small squares (or smaller pieces if you prefer bite-sized portions). Wipe the knife between cuts for the cleanest edges.