Preheat oven to 375°F and grease a baking dish.

Toss rhubarb with sugar, cornstarch, and vanilla until coated and slightly juicy.

Melt sugar in a saucepan until amber, then whisk in butter followed by cream until smooth.

Stir in miso paste until fully incorporated and silky.

Mix flour, oats, brown sugar, ginger, and salt, then rub in cold butter until crumbly.

Spread rhubarb in the dish, drizzle caramel over it, and top with crumble mixture.

Bake until golden and bubbling, then cool briefly before serving warm.