Make pudding by mixing 5.1 ounce package with 3 cups of cold milk (if your package has difference measurements of milk, follow those). Whisk to combine until it's thickened. Place in the fridge to thicken a little more until we need it.
Make whipped cream by adding heavy cream, sugar, and vanilla to the bowl of a mixer. Beat with whisk attachment until thickened and stiff peaks form. Set aside.
Layer 1/2 of the ladyfingers on the bottom of a trifle dish. Slowly pour 1/4 cup of Sherry wine over the ladyfingers. With a slotted spoon, scoop half of the thawed mixed berries over the ladyfingers. They should be strained enough with the spoon, but don't worry if a little extra juice gets in there.
Layer 1/2 of the prepared pudding over the berries, making sure that they are completely covered. Add 1/2 of sliced strawberries over the top of the pudding. If you want a nice presentation, you can line the edge with strawberry slices standing straight up. Layer 1/2 of the whipped cream over the strawberries, completely covering them.
Repeat layers. Sprinkle toasted almonds (that have cooled) over the top layer of whipped cream. If the almonds are still warm, they will melt the whipped cream so make sure they have cooled. Let the mixture set in the fridge for at least 2 hours before serving (ideally overnight, if possible).