Place chocolate and butter in medium bowl. Whisk 1/4 cup sugar, flour, and cocoa powder in small bowl. Bring milk and vanilla to boil in heavy small saucepan. Gradually whisk hot milk mixture into sugar mixture to blend. Return mixture to same saucepan. Cook over medium-high heat until thick paste forms, stirring constantly, about 2 minutes. Scrape mixture into bowl with chocolate and butter; stir until chocolate is melted (mixture may look curdled). Add egg yolks and whisk until mixture looks shiny and creamy. (Soufflé base can be prepared 1 day ahead. Press plastic wrap directly onto surface and refrigerate. Bring soufflé base to room temperature before continuing.)
Butter eight 3/4-cup soufflé dishes or custard cups; dust with sugar. Using electric mixer, beat egg whites until frothy. With mixer running, gradually add 3 tablespoons sugar, then salt; beat just until soft peaks form. Fold 1/3 of whites into soufflé base until well combined. Gently fold in remaining egg whites just to blend (some white streaks may remain). Divide batter among prepared dishes. Place dishes on rimmed baking sheet. (Can be prepared 2 hours ahead. Let stand at room temperature.)
Preheat oven to 350°F. Bake soufflés until puffed above rim of dish, tops are flat, and edges are set, about 12 minutes. Serve immediately with Cardamom Crème Anglaise.
Test-kitchen tip: To crack cardamom pods without losing the tiny seeds, crush them in a mortar with a pestle, or place the pods in a resealable plastic bag, then crush with a rolling pin or meat tenderizer.