Preheat the oven to 400°F. In a small skillet, melt 1/2 T. of butter and sauté the jalapeños in it until soft, about two minutes. Let them cool, then place them in a small bowl with the cheddar cheese and coat them with 1 T. of the flour. Combine the remaining flour with the baking powder and salt. Cut in the remaining butter with a pastry blender, or fork until the butter bits are pea sized.
Lightly whip two of the eggs and cream and add to the flour-butter mixture. Using a spoon, fold the mixture until it begins to come together. Add the cheddar-jalapeño mixture to the dough and mix until everything is incorporated.
Turn out the dough onto a well-floured surface and knead gently for less than one minute. Pat dough out to a 3/4- to 1-inch thickness and either cut into 8 triangles or the shape of your choice with a biscuit cutter. Make an egg wash by beating the remaining egg with a teaspoon of water. Brush the scones with egg wash and place on a parchment-lined (or well-oiled) baking sheet. Bake for 25 minutes or until golden brown.