For the raspberry and blueberry sauces sauce:

1. Preheat the oven to 385°F. Spray 2 rimmed baking sheets with nonstick vegetable oil spray. Arrange the raspberries in a single layer on one baking sheet and the blueberries on the other and roast for 30 minutes, until the berries have collapsed and released their liquid and it has thickened.
2. Remove from the oven and add the dried raspberries and half the vanilla bean paste, nutmeg, and salt to the roasted raspberries and stir gently.
3. Add the dried blueberries and the remaining half of the vanilla bean paste, nutmeg, and salt to the roasted blueberries and stir gently. Return both to the oven for 3 to 5 minutes to heat through.
4. Pass the raspberry mixture through a fine-mesh sieve into a bowl, using a wooden spoon to stir and mash to get the maximum amount of berry mixture through the sieve.
5. Let cool, rinse and dry the sieve, and repeat with the blueberries, straining them into a separate bowl. Refrigerate in covered containers until chilled.

While the berries are roasting, start the waffle batter:

1. In a large mixing bowl, sift together the flour, 3 tablespoons of the brown sugar, baking powder, and salt.
2. In the bowl of a stand mixer fitted with a kneading hook attachment, combine the yeast, warm water, and the remaining 1 tablespoon brown sugar and mix gently to blend. Let stand for 3 to 5 minutes, until the yeast begins to bubble. Add the flour mixture, eggs, milk, butter, vanilla bean paste, and nutmeg (in that order, so the yeast isn’t touching the salt, eggs or butter directly at first) and mix at low speed to combine. Increase the speed to medium-high and knead for 1 minute.
3. Cover with plastic wrap and refrigerate overnight or until doubled in volume (up to 12 hours).
4. When you are ready to make the waffles, let the batter come to room temperature while you preheat the waffle iron. Scoop the batter into the waffle iron and cook according to the manufacturer’s instructions, usually for 2 to 3 minutes per side.

To serve:

1. Cut 1 waffle along its natural lines into 4 sections. Place 1 piece on a plate, top with a scoop of ice cream and drizzle raspberry and blueberry sauce over it. Top with more waffle sections, ice cream and sauce, ending with a waffle on top to make a stacked “sandwich.”
2. Garnish with a dollop of whipped cream, fresh fruit, and a fat pinch of grated nutmeg, and more sauce if you wish. Repeat with the remaining waffles and serve immediately.