To make the Terrine: Pour 2 tablespoons cold water into a small bowl and sprinkle the gelatin over the surface. Let sponge, allowing the gelatin to absorb the water, about 3 minutes.
While the tea is still hot, add the sponged gelatin, sugar and honey and whisk until dissolved. Set aside and let the gelatin relax and mature and cool at the same rate as the liquid so it doesn't separate when chilling.
Place the berries in a 9 by 5-inch loaf pan or divide them among individual molds. Pour in the peach liquid. Refrigerate until chilled and firm, at least 3 hours.
To make the garnish: Whisk the egg white in a bowl to break up the tightness of the albumin. Spread the sugar out in a shallow bowl. Dip herb sprigs (the tops) and leaves (the larger bottom ones) in the egg white, shake them off a bit then dredge in the sugar. Set on a wire rack to dry a few minutes or overnight.
When ready to serve, dip the bottom of the pan into hot water for 10 seconds. Flip the terrine out onto a serving platter and garnish with the herb sprigs. Serve in slices.