Caramel Slice

Ingredients

Base

1 cup flour, plain/all purpose
½ cup brown sugar , loosely packed
½ cup desiccated coconut ¹
125g / 4.5oz unsalted butter , melted

Caramel filling

125g / 4.5oz unsalted butter , roughly chopped
½ cup (80g) brown sugar , loosely packed
1 teaspoon vanilla extract (or essence)
395g / 14oz sweetened condensed milk (1 can, 300mL) ²

Chocolate Topping

200g / 7oz dark or milk cooking/melting chocolate
1 tablespoon (20mL) vegetable oil

Method

Base

Preheat oven to 180°C/350°F (fan 160°C)
Grease and line a 28 × 18cm (lamington pan) / 7" x 11" rectangle pan with baking paper. Have overhang for ease of removal.
Mix together Base ingredients and press into a pan. Use a spoon followed by a spatula or egg slide.
Bake for 15 minutes until the surface is golden. Cool in fridge if you have time. ³

Caramel

Lower oven to oven to 160°C/320°F (fan 140°C)
Place butter, sugar and vanilla in a saucepan over medium low heat. When the butter is melted, whisk to combine with sugar, then just leave it until it comes to a simmer.
When bubbles appear, add condensed milk. Whisk constantly for 5 minutes (using a spoon) ⁴, until you start getting some big slow bubbles on the base. When stirring, make sure to keep moving the layer on the bottom of the saucepan.
Once bubbles start appearing, whisk for 1 minute, then pour onto Base. Tilt pan to spread evenly.
Bake for 12 minutes. Don't worry if you get splotchy brown bits (this happens with ovens that don't distribute heat evenly).
Cool on counter for 20 minutes then refrigerate 30 minutes - bottom of pan should be warm but surface cool (not cold) to touch. ⁵

Chocolate

Place chocolate and oil in a microwave proof bowl. Microwave in 30 second bursts, stirring in between, until chocolate is fully melted (takes me 4 × 30 sec).
Pour over caramel, spread with spatula. Then gently shake pan to make the surface completely flat.
Refrigerate 1 hour or until set. Remove from fridge and leave out for 5 minutes to take chill out of chocolate slightly. Then cut into bars or squares to serve! ⁶ ⁷

Notes

[1] Desiccated coconut is finely shredded coconut, not the large flakes.
[2] Sweetened condensed milk - Do not use skim (low fat), as caramel will not set. Also ensure you use sweetened condensed milk (thick sweet milk) that comes in cans, NOT evaporated milk.
[3] Cooling base - creates a neater line between caramel and biscuit layer. It's not really necessary.
[4] Caramel - If you don't stir constantly, little brown specks will appear, being caramel caught on the bottom of the saucepan. It's not a major problem if you have some brown specks, won't affect flavour just visual. If desperate, strain them out.
[5] Smooth chocolate - The refrigeration times is such that the caramel is mostly set, cool but not cold. That way the chocolate doesn't set too quickly when you pour it on, so when you shake the pan it will spread out evenly.
If you want to make a textured top, refrigerate the caramel until fridge-cold - 1 hr+ in the fridge. When the chocolate is poured on, it will firm up faster. As it starts to thicken, use a spatula or knife back and forth across the surface.
[6] To slice neatly, remove from the fridge an hour before cutting (in winder). A warm knife can help. Don't make the knife too hot otherwise the chocolate melts when you cut it and smears into the caramel.
[7] Storage - Airtight container for up to 5 days, but if it's so hot that the chocolate melts, keep it in the fridge and bring to room temperature before serving.

Recipe makes 12-16 servings

Source: https://www.recipetineats.com/caramel-slice/