Tomato-Butter Roast Chicken

Ingredients

• 1 tsp. ground cumin
• 1 tsp. ground mustard
• 1/4 tsp. cayenne pepper
• 1 tbsp. plus 1 tsp. kosher salt, divided, plus more
• Freshly ground black pepper
• 1 (3 1/2- to 4-lb.) whole chicken 
• 1 1/2 lb. baby Yukon potatoes, quartered 
• 2 large leeks, white and light green parts sliced into 1/2" rounds
• 1 tbsp. extra-virgin olive oil
• 1/2 c. (1 stick) unsalted butter, melted
• 1/4 c. tomato paste
• 1 tbsp. fresh thyme leaves

Description

1. Step 1In a small bowl, combine cumin, mustard, cayenne, 1 tablespoon salt, and several grounds of black pepper.
2. Step 2Pat chicken dry. Rub spice mixture all over chicken. Let sit at room temperature 1 hour.
3. Step 3Preheat oven to 400°. In a large bowl, toss potatoes, leeks, and oil; season with salt and black pepper. Transfer about half of potatoes and leeks to a large Dutch oven or heatproof pot. Arrange chicken on top.
4. Step 4In a medium bowl, whisk butter, tomato paste, thyme, and remaining 1 teaspoon salt until smooth. Reserve 1/4 cup tomato butter for serving. Brush chicken all over with remaining tomato butter. Fill in gaps on sides with remaining potatoes and leeks.
5. Step 5Cover pot and roast chicken and vegetables 45 minutes. Uncover and continue to roast until an instant-read thermometer inserted into thickest part of chicken registers 165°, 35 to 45 minutes more. Let rest 15 minutes before cutting. 
6. Step 6Brush chicken with reserved tomato butter and serve with vegetables alongside.
7. Step 7Make Ahead: Tomato butter can be made 3 days ahead. Store in an airtight container and refrigerate.