Line a small square pan (or similar dish) with baking paper and lightly grease it.

In a saucepan over low heat, melt the butter until fully liquid.

Stir in the peanut butter and mix until smooth and fully combined.

Remove from heat and stir in vanilla extract.

Gradually add powdered sugar, mixing until the mixture becomes thick, smooth, and slightly stiff.

Pour into the prepared pan and smooth the top with a spatula.

Let it cool at room temperature for about 1 hour, then transfer to the fridge to fully set.

Room temperature: ~1 hour (initial set)

Refrigerator: 2–3 hours for best firmness and clean slicing

Sift the powdered sugar to avoid lumps in the fudge

Mix quickly once sugar is added — it thickens fast

For extra richness, use a little more butter (up to 2 extra tablespoons)

If the mixture feels too soft, add a bit more powdered sugar

Press it firmly into the pan so it slices neatly later

Store in an airtight container in the fridge

Keeps well for up to 1 week

Can also be frozen for up to 2 months

Best served slightly chilled for clean slices, or room temp for extra softness