A home baker has shared the simple four-ingredient recipe they swear by for the perfect brownies - and it even includes a surprising ingredient to keep the sweet treats moist.

There's no need for complex instructions or expensive ingredients either, according to the Reddit user gorcbor19.

Sharing the unique formula online, the forum user explained that they first tried the recipe when they realised they had all of the components in their pantry already.

The keen baker shared: "The consistency doesn't look like the picture, they're more gooey than that, but they are super tasty.

"I was surprised as this is the first 'dessert' I've made since shifting my diet to plant-based late last year. I'll definitely be making them again!"

These aren't ordinary brownies, however. The key chocolate flavour is derived from cocoa powder alone, and mashed sweet potato is cleverly used to create a moist texture that quite literally melts in your mouth.

Speaking of the baking experience with delight, the poster claimed they were "shocked at how good they turned out" given the simplicity of the recipe.

Some members of the forum expressed concern over the potential prominence of sweet potato flavour, but the original poster reassured: "My kids ate them and hate sweet potatoes. I didn't follow the recipe once, used too much sweet potato and I could taste it."

Four-ingredient brownie recipe

Ingredients

Three cups cooked sweet potato, mashed

Three-quarter cup of cocoa powder

1.5 cups nut butter

Three-quarter cup maple syrup

Method

Preparing the brownie mixture is easy to do in a hurry as all of the ingredients can be combined in one bowl.

For the smoothest consistency, a food processor is recommended, but if the sweet potato is cooked until very soft, manual mashing will suffice.

Combine the mashed sweet potato, nut butter, and maple syrup in a bowl or food processor. If using a bowl, sieve in the cocoa powder and mix thoroughly to thicken the blend.

Transfer the mixture to a small square baking tray or loaf pan. Bake in a preheated oven at 175C for 12-15 minutes. Aim to remove the brownies while they're still slightly gooey inside to achieve that irresistibly soft texture.