Canadian Butter Tarts

Before you start

A butter tart is a small, flaky pastry shell filled with brown sugar, syrup, butter and egg that bakes into a filling with a crackly top and a soft, runny middle. They are a fixture of Canadian bake sales, and people argue happily about the details: runny or firm, raisins or plain, walnuts or pecans. This version aims for a filling that flows slowly when you bite in, and treats raisins as optional.

The filling needs high heat and a short bake. A hot oven sets the pastry and caramelizes the top before the center firms; a long, slow bake turns the filling into chewy candy. Fill the shells only two thirds full, because the filling bubbles up hard in the oven and glues the tarts to the tin if it spills over.

Ingredients

• Pastry300 g (2½ cups, spooned and leveled) all-purpose flour
• 1 tbsp granulated sugar
• ¾ tsp fine salt
• 115 g (½ cup) unsalted butter — cold, cubed
• 85 g (6 tbsp) lard or vegetable shortening — cold
• 90 to 110 ml (6 to 7 tbsp) ice water mixed with 1 tsp white vinegar
• Filling165 g (¾ cup packed) light brown sugar
• 120 ml (½ cup) light corn syrup or golden syrup
• 60 g (¼ cup) unsalted butter — melted and slightly cooled
• 1 large egg — room temperature
• 1 tsp vanilla extract
• 1 tsp white vinegar or lemon juice
• ¼ tsp fine salt
• 75 g (½ cup) raisins or chopped pecans — optional

Method

1. Whisk the flour, sugar and salt. Cut in the butter and lard until the largest pieces are the size of peas. Sprinkle in the vinegar water a tablespoon at a time, tossing with a fork, until the dough holds together when squeezed. Divide into two flat discs, wrap and chill for 30 minutes.
2. Heat the oven to 200°C (400°F) with a rack in the lower third. Roll one disc at a time to 3 mm (⅛ in) thick and cut 10 cm (4 in) rounds. Press them into the muffin cups so the pastry pleats a little and stands just above the rim. Reroll scraps once to get 12 shells, then chill the tin while you make the filling.
3. Whisk the brown sugar, syrup and melted butter until smooth. Whisk in the egg, vanilla, vinegar and salt just until combined. Whisking hard adds air, which makes the filling foam and rise over the edges.
4. Divide the raisins or pecans among the shells if using. Pour the filling over them, filling each shell no more than two thirds full.
5. Bake for 15 to 18 minutes, until the pastry is golden and the filling is bubbling and puffed across the surface. The center should still look liquid under the crust when you jiggle the tin.
6. Cool in the tin for 5 minutes, then run a thin knife around each tart to free any sticky filling. Lift the tarts onto a rack and let them cool for at least 25 minutes before eating.

Tips for success

• Soak raisins in hot water for 10 minutes and pat them dry; plump raisins stay juicy instead of burning on top.
• For a firmer filling that will travel well, bake 2 to 3 minutes longer, until the bubbling slows.
• Set the muffin tin on a rimmed baking sheet. Any filling that does escape lands there instead of on the oven floor.

Substitutions

Lard or shortening

Use all butter (200 g total) for more flavor. The pastry will be a little less tender and should be kept cold throughout.

Corn syrup

Maple syrup gives a looser, maple-flavored filling; bake until it bubbles well, and expect it to run more. Golden syrup gives a deeper, buttery taste.

Light brown sugar

Dark brown sugar adds a stronger molasses flavor and a darker filling with the same texture.

Variations

Butter tart squares

Press a shortbread base of 150 g flour, 115 g butter and 40 g sugar into a 20 cm (8 in) square pan, bake 15 minutes, add a double batch of filling and bake 20 to 25 minutes.

Maple walnut

Use 60 ml maple syrup and 60 ml corn syrup, and fill with toasted walnuts.

Troubleshooting

The filling overflowed and stuck to the tin

The shells were overfilled or the filling was overwhisked. Fill to two thirds, whisk gently and free the tarts with a knife while they are still warm.

Filling is firm and chewy rather than runny

It baked too long or too slowly. Use a full 200°C (400°F) and pull the tarts once the surface is bubbling all over.

Pastry is pale and soft on the bottom

The rack was too high or the oven not fully heated. Bake in the lower third so the base gets direct heat.

Storage

Keep the tarts in an airtight container at cool room temperature for 1 day, or refrigerate for up to 4 days. The filling firms in the fridge; let them stand at room temperature for 30 minutes before serving. Baked tarts freeze well for up to 2 months.

Safety notes

Do not taste the raw dough or uncooked filling, which contain raw flour and egg. Contains wheat, egg and milk, and tree nuts if you add pecans or walnuts.