Preheat oven to 425°F.
In a small bowl, whisk 3 tbs. sugar and lemon zest for about 1 minute, or until sugar is fragrant and moist.
Arrange peaches, cut side up, in a 13x9-inch baking dish.
Pour 2/3 cup water into dish.
Sprinkle lemon sugar mixture over peaches and roast for 25 to 30 minutes, or until peaches are slightly softened and have released their juices.
Meanwhile, lightly spray a small baking sheet with nonstick spray.
In a medium heavy saucepan over high heat, bring remaining sugar, honey, and 2 tbs. water to a boil, stirring constantly.
Reduce heat to medium-high and cook, without stirring, for about 5 minutes, or until a candy thermometer reaches 305°F.
Remove from heat and whisk in baking soda just until blended and mixture begins to bubble.
Gently pour hot mixture onto prepared baking sheet and cool.
Break honeycomb into small pieces and reserve in an airtight container.
Spoon 1/2 cup Breyers® Natural Vanilla Ice Cream into each of 8 bowls.
Top with warm roasted peaches and warm juices.
Sprinkle with honeycomb pieces and serve immediately.