Heat oven to 450. Spray cookie sheet with cooking spray. In large bowl, stir flour, sugar, baking powder,cream of tartar and salt with fork. Cut in 1/2 butter,until mixture looks like coarse crumbs. Add 3/4 c. milk and stir with fork just until moistened.
On lightly floured surface, knead dough 10-12 times or until almost smooth. Roll dough into a 15x9 rectangle. In small bowl, stir in filling ingredients(nuts maple syrup, butter, and cinnamon) Spread filling over dough. Fold dough lengthwise in half to make a 15x4 inch rectangle. Cut rectangle crosswise into 15 1-inch-wide strips. Holding a strip at each end, twist in opposite directions twice. Place twisted strip 1 inch apart on the cookie sheet pressing both ends down
Bake 10-12 minutes or until golden brown. Remove carefully from cookies sheet immediately to rack and cool.
In a small bowl stir together the glaze ingredients, powdered sugar the maple syrup adding milk a little at a time if necessary, until thin enough to drizzle. Drizzle glaze over warm biscuits. Serve warm or cooled.