Place the red candy melts in a microwave-safe bowl. Microwave on high for 2–3 minutes, stirring every 15–30 seconds, until fully melted and smooth. Be sure to stir frequently to prevent overheating.
Repeat the same process with the pink candy melts in a separate bowl. Keep the two colors separate.
Remove the lid and foil seal from the container of frosting. Microwave for 45 seconds to 1 minute, or until completely melted and smooth. If using heart sprinkles, set aside about ½ teaspoon of unmelted frosting for later.
Stir the strawberry extract into the melted frosting until well combined.
Divide the frosting evenly between the two bowls of melted candy melts—half into the red, half into the pink.
Stir each mixture vigorously until fully combined and smooth. The mixture may thicken slightly; this is normal.
Line an 8x8-inch square pan with parchment paper, leaving some overhang for easy removal.
Alternate spooning or pouring the red and pink mixtures into the pan in random spots. Gently tap the pan on the counter between pours to help the fudge level out and release air bubbles.
Once all of the mixture has been added and smoothed out, generously sprinkle the top with Valentine’s-themed non-pareils.
Refrigerate for 2 hours, or until completely set.
Once chilled, remove the fudge from the pan and cut into squares.
Optional: Use the reserved frosting to dab a small amount onto the back of a heart sprinkle and press it into the center of each fudge square for an extra cute finishing touch.