Make filling: In a 4-quart saucepan or deep sauté pan (9–12 inches in diameter), combine apple juice, ginger, cinnamon stick, nutmeg, cardamom, and pepper. Bring to a boil, reduce heat to low, add tea bags, and simmer 10 minutes. Remove tea bags and strain liquid; discard solids. Add additional juice if needed to measure 2 cups. Return to saucepan. Add apples, raisins, and sugar. Cover and cook over low heat 5–10 minutes, or until apples are just tender. Cover to keep warm over low heat.

Make topping: Mix milk and vinegar in a 1-cup measuring cup; set aside 5 minutes. Mix sugar and ¼ teaspoon cinnamon in a small bowl. Set aside. Place a wire mesh strainer over a medium bowl. Add flours, baking powder, baking soda, 1 teaspoon cinnamon, and salt. Stir with wire whisk to sift ingredients into bowl, and whisk again to aerate ingredients.

Stir oil and vanilla into milk. Pour into dry mixture, and stir just until a soft batter forms. Drop rounds of batter over simmering fruit. Cover saucepan with a tight-fitting lid or aluminum foil. Simmer on low heat 20 minutes. Uncover carefully. The slump is ready when biscuits feel firm when lightly tapped. (They will be pale.) Cover and a simmer a few minutes longer if needed. Serve warm.