First, add the blackberries and water to a saucepan.

Mash the blackberries with a fork to help them soften more quickly.

Bring to a boil, then reduce to a simmer for 5–7 minutes. Remove from the heat.

Pour the mixture through a fine-mesh sieve set over a bowl, pressing gently to extract as much juice as possible. Discard the remaining pulp.

Stir the lemon juice and sugar into the blackberry juice.

Return the blackberry juice to the saucepan, bring to a boil, then simmer for 2–3 minutes until the sugar has dissolved. Allow it to cool completely before adding it to the mascarpone mixture to prevent splitting.

Pour the heavy cream into a large bowl and whisk until stiff peaks form, about 3–5 minutes. Set aside.

In a separate bowl, whisk together the mascarpone, sugar, and vanilla or almond extract until smooth, about 1 minute.

Fold one-third of the whipped cream into the mascarpone mixture. Repeat with the remaining whipped cream until fully incorporated.

Fold one-third of the cooled blackberry juice into the mascarpone mixture. Continue adding the remaining juice in two additions, folding gently after each addition until combined. Do not overmix, as this may cause the filling to split and become grainy.

The blackberry mascarpone filling should now be smooth and evenly coloured.

Dip each ladyfinger into the blackberry mixture for 2–3 seconds per side. For a softer texture, soak for 3–5 seconds per side.

Arrange the soaked ladyfingers in an even layer across the base of your serving dish.

Spread half of the blackberry mascarpone filling evenly over the ladyfingers.

Repeat with another layer of soaked ladyfingers.

Spread the remaining blackberry mascarpone filling over the top, smoothing it into an even layer. Cover and refrigerate for at least 6 hours, preferably overnight, for the best flavour and texture.

Add the blackberries and water to a saucepan.

Bring to a boil, then simmer for 5–7 minutes until the blackberries have softened. Allow to cool completely.

Blend until smooth.

Stir in the cornstarch slurry, sugar, and lemon juice. Bring to a boil and simmer for 2–3 minutes, stirring continuously until smooth and thickened.

For an extra smooth, glossy finish, strain the topping through a fine-mesh sieve into a bowl. Stir in the butter until completely melted and fully incorporated.

Allow the topping to cool completely before spreading it over the tiramisu to prevent the mascarpone filling from splitting.

Once the tiramisu has chilled and set, pour the cooled blackberry topping over the surface.

Spread into a smooth, even layer, using just enough to cover the surface. Avoid adding too much, as excess topping may spill over the sides when serving.

Finish with fresh blackberries and mint leaves.

Serve chilled and enjoy.