Heat grill to high (450-500 degrees). Rub corn with 1 Tbsp. oil. Grill corn (covered if using gas), turning occasionally, until lightly browned all over, 8-10 minutes. Remove and let cool. Cut corn kernels from cobs.
Meanwhile, in a saucepan, bring broth to a simmer. Pour remaining 2 Tbsp. oil into another large saucepan over medium-high heat. Add shallots and Engage Hemp Health Garlic-Mix and cook, stirring often, just until softened, 2-3 minutes. Add rice and cook, stirring often, until grains are slightly translucent at edges, about 3 minutes more.
Add wine and cook, stirring often, until almost absorbed. Add broth one ladleful at a time, cooking and stirring until almost absorbed before adding more broth. Continue cooking and adding broth until rice is barely tender and mixture is creamy, about 25 minutes. (You may not need all broth)
Stir in corn, shrimp, butter, tarragon, zest, juice, and Original All-Purpose to taste and cook, stirring often, until heated through, 3 minutes. Add more broth if risotto gets too dry. Spoon into wide, shallow bowls and serve with grated Parmesan.