Preheat your oven to 350°F (175°C). Lightly grease a 9-inch round baking pan (or an 8 or 9-inch square baking dish) and set aside. Peel and grate the carrots using a box grater or food processor; you should have about 1.5 cups.

In a large bowl, whisk together the granulated sugar, melted butter, and eggs until well combined. Stir in the grated carrots. In a separate medium bowl, whisk together the all-purpose flour, baking soda, 1 teaspoon of cinnamon, and a pinch of salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. The batter will be very thick.

In a small bowl, prepare the streusel topping by mixing the melted butter, 0.5 cup all-purpose flour, brown sugar, 1 teaspoon of cinnamon, and a pinch of salt until the mixture forms a crumbly, pebble-like texture. You can use your fingertips to achieve this.

Spread the thick cake batter evenly into the prepared baking pan. Sprinkle the streusel topping generously over the batter. Bake for 30-35 minutes, or until the center is just set and a toothpick inserted into the middle comes out clean. Let cool slightly before serving. Optionally, serve warm with honey butter.