1. Prepare the Chiles:

• Roast the poblano chiles over an open flame or under a broiler until the skin is charred and blistered.
• Place the chiles in a sealed plastic bag or covered bowl to steam for about 10 minutes.
• Gently peel off the charred skin, being careful not to tear the chiles.
• Make a small slit on one side of each chile and remove the seeds and veins.
• Stuff each chile with the cheese and set aside.

2. Prepare the Batter:

• In a bowl, whisk together the flour, baking powder, ground cumin, and fine salt.
• Gradually add the lager beer, stirring until the batter is smooth and has a slightly thick consistency.
• Lightly dredge the stuffed chiles in flour to help the batter stick.

3. Deep Fry the Chiles:

• Heat vegetable oil in a deep skillet or pot to about 350°F (175°C).
• Dip each stuffed chile into the batter, ensuring it is fully coated.
• Carefully lower the chile into the hot oil and fry until golden brown, turning as needed.
• Drain the fried chiles on a paper towel and sprinkle lightly with salt.

4. Prepare the Mexican Tomato Sauce:

• Blend the chopped tomatoes, onion, garlic, coriander sprigs, serrano chile, kosher salt, and cinnamon until smooth.
• Heat the mixture in a saucepan over medium heat, stirring occasionally, until it thickens and flavors meld.

5. Serve:

• Serve the fried chiles rellenos hot, drizzled with the warm Mexican tomato sauce.
• Garnish with fresh cilantro or a sprinkle of queso fresco if desired.