Preheat oven to 425°F.
Line baking sheet with parchment paper.
Mix flour, baking powder, salt, garlic powder together.
Cut cold butter into flour mixture until crumbly.
Add buttermilk and cheddar cheese to mixture.
Stir until dough just comes together gently.
Combine crab meat, mayonnaise, Old Bay, green onion.
Roll dough into 8 equal portions carefully.
Flatten each portion into small circles gently.
Place crab filling in center of circles.
Fold dough over filling and seal edges.
Place stuffed biscuits on prepared baking sheet.
Bake for 12-15 minutes until golden brown.
Melt butter with lemon juice and zest.
Brush hot biscuits with lemon butter mixture.