In a pot, melt the butter on medium heat until it begins to brown, about 5 minutes. Add the rice and stir, coating the rice in the browned butter for another 2 minutes. Add milk, sugar, vanilla bean and bring to a boil, then reduce to a simmer, stirring every 5 minutes for about 45 minutes until the rice is cooked but still al dente. Remove from heat, cover with plastic wrap, let cool, then put in the refrigerator.
For the ganache:
In a small pot, heat 1/2 cup cream, add the chopped milk chocolate and stir until melted. Set aside to cool.
In a bowl, whip the remaining cream with the icing sugar. Set aside in the refrigerator.
For the almond slivers:
Heat almond slivers in a pan until they become golden brown. Lay the almonds on a tray lined with parchment paper. Drizzle with honey and sprinkle with coarse sea salt. Set aside.
Fold the whipped cream into the rice pudding mixture and refrigerate for 2 hours. Dish the rice pudding into small serving bowls and garnish with chocolate ganache and almond slivers on top.