Add the plain flour, icing sugar, and salt to the bowl of your food processor. Give it a few quick pulses to combine everything. Next, toss in the very cold, cubed butter and blend until the mixture turns into fine, sandy crumbs—this is the secret to a perfectly tender texture!

Crack in the egg and mix until the dough starts to come together. To check if it's ready, grab a small handful and press it in your palm—if it holds its shape, you're good to go! If it still feels too dry and crumbly, add a few drops of ice-cold water and mix again until you achieve that perfect consistency.

Gather the dough into a ball and place it between two large sheets of baking paper. Use a rolling pin to roll it out into a smooth, even disk about 4mm (1/8 inch) thick. Transfer it onto a flat tray and let it chill in the fridge for at least an hour—or, if you’re planning ahead, you can leave it for up to 24 hours.

Once the dough is nicely chilled, peel off the baking paper and use a round or fluted cookie cutter to cut out small pastry disks, making sure they’re at least as wide as the openings of your muffin cups. Gather any leftover dough, roll it out again, and refrigerate for another 2 hours before cutting out more tart shells. No dough goes to waste!

Carefully place each pastry disk into the muffin pan, gently pressing it down to fit snugly. Make sure there are no air bubbles by lightly pressing into the corners so the dough fully touches the pan on all sides. To ensure the pastry holds its shape, gently push the sides against the pan.

Pop the pan back into the fridge and let the pastry chill and rest for at least an hour—though if you have the time, letting it sit overnight will give you the best results!

Preheat your oven to 160°C (325°F). Take the chilled pastry and gently prick the bottoms with a fork to prevent air pockets from forming. Pop the pan into the freezer while the oven finishes preheating—this helps the pastry hold its shape while baking.

Once ready, place a crumpled piece of baking paper over each crust and fill them with pie weights, dried beans, or rice to keep them from puffing up. Now they’re all set for a perfectly crisp and even bake!

Bake the pastry shells for 15 minutes, then carefully remove the baking paper and weights. Return them to the oven and bake for another 12 to 15 minutes, or until they’re fully baked and feel dry to the touch. Once done, transfer the pan to a wire rack and let the crusts cool completely before filling them with your toppings!

Pour the cream into a small bowl and heat it in the microwave for 30 seconds to 1 minute, just until warm. Set it aside for later.

In a small saucepan, add the brown sugar and cubed butter. Set the heat to low-medium and let everything melt together, stirring occasionally. Once fully melted, allow it to gently simmer for a couple of minutes.

Carefully pour the warm cream into the melted brown sugar mixture—be cautious, as it may bubble up! If the cream has cooled, give it a quick reheat before adding it. Stir well with a heat-proof spatula until the mixture is silky smooth, then let it cook for another 2 minutes on low-medium heat, stirring occasionally.

Stir in the salt and vanilla paste, mixing until fully combined. Let the sauce simmer gently for 3 to 5 minutes on low-medium heat, allowing it to thicken slightly.

Carefully pour the hot butterscotch sauce into a clean pouring jug—watch out, it’ll be very hot! Pour the warm sauce into the baked tartlet crusts right away. Give each tart a gentle tap against a hard surface to release any air bubbles and ensure a smooth, even top.

Transfer the tarts to the fridge and let them chill for at least 2 hours, or until you're ready to serve. The longer they chill, the thicker and more set the filling will become, so feel free to let them rest overnight for the best texture!