Also delicious with anchovy butter!
Preheat the oven to 180°C (356°F).
For the butter, press the pieces of cod liver through a fine mesh sieve using the back of a spoon to create a mousse-like texture. Mix the mousse with the butter and cognac until smooth. Season with salt and white pepper. Transfer the mixture onto a piece of plastic wrap and roll it into a log. Let it firm up in the refrigerator for at least 30 minutes.
Line a baking sheet with parchment paper. Spread the zucchini, eggplant, and bell pepper over it. Sprinkle with salt, pepper, and thyme, then drizzle with olive oil. Roast the vegetables in the oven for about 25 minutes until golden brown.
Place the baguette pieces on a wire rack in the preheated oven and bake for 5-7 minutes until crispy and golden brown. Remove from the oven and let them cool.
Remove the vegetables from the oven and let them cool. Mix in a few drops of olive oil and season with salt and pepper.
Top the toasted bread with the grilled vegetables and drizzle with balsamic vinegar. Distribute the cod liver butter over the vegetables and place the bruschettas in the oven for another 2 minutes. Garnish with basil leaves and drizzle with extra balsamic vinegar. If the vegetables are still warm enough, you can let the butter melt over them outside the oven.