Prep the mold: Lightly grease a 1.5 to 2-quart pudding basin, mixing bowl, or loaf pan. Line with plastic wrap, leaving generous overhang to fold over the top later. This makes unmolding easy.

Make the berry syrup: In a saucepan, combine 2 cups mixed berries (reserve 1 cup for layering), sugar, lemon juice, zest, vanilla, and a pinch of salt. Cook over medium heat for 3–5 minutes until berries release their juices and the sugar dissolves. You want juicy, not jammy.

Taste and adjust: Add a little more lemon juice if it tastes flat, or a touch more sugar if your berries are very tart. Remove from heat and let it cool for 5 minutes.

Prep the bread: Slice off crusts if you haven’t already. Cut some slices into triangles or strips to help patch gaps. The goal is a snug bread “shell” with no holes so the syrup doesn’t leak out.

Line the base: Dip one side of a bread slice lightly into the warm berry syrup and press syrup-side down into the bottom of the lined bowl. Repeat with more slices to cover the base.

Build the walls: Dip and line the sides of the bowl with overlapping bread pieces, slightly pressing them together. Patch any gaps with small pieces. Keep the rest of the bread and syrup handy.

First fruit layer: Spoon some syrupy berries into the bottom. Add a few fresh reserved berries and a layer of peach slices. Don’t overpack; aim for an even layer.

Add bread layer: Place a single layer of plain bread over the fruit, then drizzle with a little syrup so it softens. This keeps the structure neat.

Repeat the layers: Continue layering fruit and bread, finishing with a final bread “lid.” Drizzle enough syrup over the top to moisten everything. Reserve a few tablespoons of syrup in case you need to touch up dry spots later.

Seal and weight: Fold the plastic wrap over the top. Place a small plate or saucer that fits just inside the bowl on top, then add a light weight (a can or jar). This helps compress and set the pudding.

Chill to set: Refrigerate for at least 6 hours, preferably overnight. The bread will absorb the juices and firm up so it slices cleanly.

Unmold: Remove the weight and plate. Peel back the wrap, place a serving plate over the bowl, and invert. Lift off the bowl and plastic. If there are pale spots, brush with the reserved syrup.

Serve: Slice with a sharp knife. Serve with whipped cream, yogurt, or crème fraîche, and garnish with mint if you like.