Preheat the oven to 400 degrees. While the oven's heating up, saute your jalapeños in a small amount of butter for about 2 minutes. Transfer the jalapeños to a bowl to cool and toss them in 1 tablespoon of flour. The cooked butter and the flour are going to combine and make a roux which will keep the jalapeños from sinking to the bottom of the scones. Combine your dry ingredients (the remaining flour, baking powder, and salt) in a separate bowl. You want to "cut" in the butter until the butter is in very small pieces. Using a knife or fork or hard spatula, make cutting motions to incorporate the butter and flour. Whisk 2 of the eggs and add the heavy cream to it. Combine the egg mixture with the flour mixture and fold them both together. Add the cooled jalapeños and cheddar and incorporate. Transfer the dough to a well floured surface and knead for about 1 minute, until it has a biscuit-like texture. Pat out the dough until the whole piece is about 1" thick, then cut into desired pieces. You can use a knife to cut 8 triangles, or use a biscuit cutter if you like circular scones. Align your scones on a well greased sheet tray or parchment lined tray and brush each one with an egg wash made from whisk your last egg with 1 tsp or so of water. Bake at 400 degrees for about 25-30 minutes.