Preheat the oven to 350º with oven rack in the middle. Line baking sheet with a silicone baking mat or heavy-duty aluminum foil buttered generously. In a large bowl, whisk together the oats, flour, sugar, cinnamon, chili powder, baking soda and salt. Stir in almonds. Add butter, half-and-half (or milk), corn syrup and vanilla. Stir to combine. Scoop heaping teaspoons of batter onto the prepared sheet at least 3 inches apart, six cookies per sheet. Bake one sheet at a time until the cookies are flat and browned around the edges, 7 to 9 minutes. Cool cookies on the sheet several minutes, until firm enough to transfer to a cooling rack. When all cookies are baked, melt the chocolate in a metal bowl set over a pan of simmering water. Using a very small tipped pastry bag or the tines of a fork, drizzle the chocolate in a zigzag pattern over the tops of the cookies.