Preheat oven to 425°F and line baking sheet with parchment paper.
Add the flour, sugar, baking powder, xanthan if using, and salt and pulse to combine. Add the butter and pulse until it is roughly the size of peas. Add the cheese and chopped jalapeno peppers, and pulse a few times more just to combine.
Whisk the eggs and heavy cream together in a bowl. Add to the food processor and pulse just until everything comes together. It should be a little crumbly still.
Pour mixture out onto the prepared baking sheet and pat into a disk that is about 1½ inches thick. Cut into 6 triangles and using a spatula, evenly space the scones on the baking sheet. Brush each scone with heavy cream, sprinkle with cheese and top with a slice or two of jalapeno.
Bake for 14-16 minutes, or until the scones are lightly golden brown.
Remove from oven and leave on the pan to cool completely.
Scones can be kept at room temperature and are best if eaten within a day or two.