1. Preheat oven to 325ºF. Line an 8-inch square pan with foil, allowing a 1-inch overhang. Coat with cooking spray.
2. In a food processor, blend almonds, cocoa, sugar, chocolate, baking soda and salt until ground. Pulse in dates, almond milk, oil and vanilla until a smooth paste forms.
3. Beat egg whites until medium peaks form. Stir in one-third of almond mixture, then fold in remaining mixture. Spread in baking pan and sprinkle with chocolate chips, if desired.
4. Bake until a toothpick inserted 1 inch from edge comes out almost clean, about 30 minutes. Let cool in pan on a wire rack.