Make the vanilla pastry cream first and chill it.
Warm the milk until it’s just warm (not hot), stir in the yeast, and let it sit 5 to 10 minutes until foamy.
Whisk egg, egg yolk, sugar, vanilla, and salt. Add the yeast milk, then mix in flour and softened butter to form a dough. Knead 10 to 12 minutes until smooth, then let rise 45 minutes until doubled.
Simmer raspberries, sugar, butter, and a pinch of salt until broken down and jammy. Cool completely.
Roll dough into a rectangle (about 0.5 cm thick), spread on the raspberry filling (add lemon zest if you want), roll into a log, and slice into 12 swirls. Let rise 45 minutes.
Bake at 350°F (175°C). Brush with egg wash, press a small dip in the center, add a spoon of pastry cream and 3 raspberries, then bake about 15 minutes until golden.