Preheat oven to 400 degrees; grease a baking sheet or line with parchment. In a medium bowl, combine the flour, sugar, baking powder, lemon zest and salt. Cut in the butter with a fork or a heavy-duty electric mixer until the mixture resembles coarse crumbs. In a small bowl, whisk together the eggs and cream. Add to the dry mixture and stir until a sticky dough is formed. Turn out the shaggy dough onto a lightly floured surface and knead gently about 6 times, just until the dough holds together. Divide into two equal portions and pat each into a 1 inch thick round about 6 inches in diameter. With a knife or straight edge, cut each round into quarters, making 4 wedges. The scones can also be formed by cutting out with a 3-inch biscuit cutter to make 10 to 12 smaller scones. Place the scones about 1 inch apart on the baking sheet. Sprinkle the tops with the cinnamon sugar, if desired. Bake for 15 to 20 minutes until crusty and golden brown. Serve immediately with butter and jam.