Line a mini muffin pan with 24 mini parchment papers.
Cut each yeast roll in half and form each half into small balls and place, seam side down, in the parchment papers.
Cover the pan of yeast balls with plastic wrap and set in a draft-free space until they have risen to twice their size. About 45 minutes.
In a large, wide cast iron or stainless steel skillet set over medium heat, add the oil and when it is hot add the sliced onions and herbs, tossing to coat them with the oil.
Cook the onions, stirring them every 5 or 6 minutes, scraping up the fond from the bottom as it forms.
When they have reached a dark golden brown, about 45-50 minutes, add a couple tablespoons of wine or water to deglaze.
Remove the skillet from the heat, sprinkle the onions with salt and transfer them to a bowl and allow to cool to room temperature.
Preheat the oven to 350°F.
Transfer the muffin tin to the center rack of the preheated oven and bake the boules for 12-15 minutes until they are golden brown.
In a medium size saucepan set over medium heat, add the butter and when it has melted stir in the flour and cook until the mixture is a light golden color.
Whisk in the milk and cream. Increase the heat to medium-high and bring the sauce to a boil, whisking constantly, until the sauce becomes thick and smooth, about 2 minutes.
Whisk in the wine, and cook another minute to burn off the alcohol in the wine.
Remove the sauce from the heat and stir in the grated gruyere cheese, add the salt and pepper to taste.
With a small sharp knife cut the tops off of each boule and pick out the inside using a small appetizer fork.
Fill each mini boule ¾ full with a scoop of the cheese sauce. Add a portion of the caramelized onions, heaping them on top. Garnish with fresh herbs before serving at room temperature.
