In a medium bowl, combine 150g softened cream cheese, 2 tablespoons caster sugar, and 1 teaspoon vanilla extract. Mix until the texture is silky smooth and lump-free. Then, gently fold in ½ cup of blueberries, being careful not to crush them if you're using fresh ones. If you’re working with frozen blueberries, make sure they’re thawed and drained to avoid a soggy filling.This rich, tangy filling mimics the flavor of classic blueberry cheesecake, creating a delicious surprise inside every slice.
Take your day-old brioche loaf and slice it into 8 thick slices. You’ll be building 4 sandwiches, so make sure the slices are even in thickness for consistent cooking. On four of the slices, spread a generous layer of the cream cheese and blueberry filling. Then, top each with a second slice to close the sandwich. Press gently around the edges so the filling stays tucked inside when frying.
Carefully dip each sandwich into the custard mixture. Let them soak for about 20 seconds on each side, ensuring the custard penetrates the bread without making it soggy. Don’t rush this step—it’s key to that perfect soft center!
Heat a generous knob of butter in a non-stick skillet or griddle over medium heat. Once the butter is melted and bubbling, gently place the soaked sandwiches into the pan.
Cook for 3–4 minutes per side, flipping once, until each side is deeply golden and crisp. The goal is to warm the filling, cook the custard through, and create that irresistible golden crust on the outside.
Cook in batches if needed, adding more butter as you go to keep things from sticking and to enhance that buttery finish.