Make the crust by combining the gluten free flour blend, tapioca starch, and salt in a food processor. Add the cold cubed butter and pulse 10 to 12 times until the mixture resembles coarse crumbs. Add the egg yolk and ice water, then pulse just until the dough comes together. Wrap in plastic wrap, flatten into a disc, and refrigerate for 30 minutes.
Preheat the oven to 375 degrees F. Roll the chilled dough between two sheets of parchment paper into a 12-inch circle. Transfer it to a 9-inch pie dish, pressing it into the bottom and up the sides. Trim any excess and prick the bottom with a fork. Line with parchment and fill with pie weights or dried beans.
Blind bake the crust for 15 minutes. Remove the parchment and weights, then bake for another 5 to 7 minutes until the bottom looks dry and lightly golden. Remove from the oven and reduce the temperature to 350 degrees F.
While the crust bakes, cook the chopped bacon in a skillet over medium heat for 6 to 8 minutes until crisp. Transfer to a paper towel-lined plate to drain.
Scatter the cooked bacon and shredded gruyere evenly over the bottom of the par-baked crust.
In a medium bowl, whisk together the eggs, heavy cream, nutmeg, salt, and black pepper until smooth. Pour the custard mixture over the bacon and cheese in the crust.
Bake for 35 to 40 minutes until the filling is set around the edges but still has a gentle jiggle in the very center. Let the quiche cool on a wire rack for at least 15 minutes. Sprinkle with fresh chives, then slice and serve.