Sand Art Brownies

INGREDIENTS

• 2 cups sugar
• 1/2 teaspoon salt
• 4 large eggs
• 1 clear glass quart jar with a tight fitting lid
• 1 cup semisweet or white chocolate chips or a combination of both
• 1 cup (2 sticks) unsalted butter, melted and cooled, plus more for greasing pan
• Food coloring
• 1/2 cup cocoa powder
• 1 cup all-purpose flour
• 2 teaspoons vanilla extract