In a small saucepan over medium heat, melt the butter. Whisk in the flour until it turns golden and a paste forms, 1 to 2 minutes.
Gradually add the warm milk, whisking constantly. Continue to whisk until the mixture thickens, 4 to 5 minutes.
Whisk in the Tillamook Sharp Cheddar Cheese and jalapeños. Stir until the cheese is melted, 1 to 2 minutes more.
Remove from the heat and stir in chili powder, cayenne and scallions. Season with salt.
Transfer the queso to a serving bowl and garnish with the cilantro. Serve with tortilla chips.
