Adjust oven rack to middle position and heat oven to 350 degrees.
Process tomatoes and onion in food processor until smooth and thoroughly pureed, about 15 seconds, scraping down bowl if necessary.
2 Tomatoes, 1 Small White Onion
Transfer mixture to liquid measuring cup; you should have 2 cups (if necessary, spoon off excess so that volume equals 2 cups).
Remove ribs and seeds from 1 jalapeño and discard; mince flesh and set aside.
2 Jalapeno Chiles
Mince remaining jalapeño, including ribs and seeds; set aside.
2 Jalapeno Chiles
Place rice in large fine-mesh strainer and rinse under cold running water until water runs clear, about 1 1/2 minutes.
2 Cups Rice
Shake rice vigorously in strainer to remove all excess water.
Heat oil in heavy-bottomed oven-safe 12-inch straight-sided sauté pan or Dutch oven with tight-fitting lid over medium-high heat, 1 to 2 minutes.
1/3 Cup Canola Oil
Drop 3 or 4 grains rice in oil; if grains sizzle, oil is ready. Add rice and cumin and fry, stirring frequently, until rice is light golden and translucent, 6 to 8 minutes.
1/2 teaspoon Cumin
Reduce heat to medium, add garlic and seeded minced jalapeños; cook, stirring constantly, until fragrant, about 1 1/2 minutes.
4 Cloves Garlic
Stir in pureed tomatoes and onions, chicken broth, tomato paste, and salt; increase heat to medium-high and bring to boil.
2 Cups Chicken Broth, 1 Tablespoon Tomato Paste, 1 ½ teaspoons Salt
Cover pan and transfer to oven; bake until liquid is absorbed and rice is tender, 30 to 35 minutes, stirring well after 15 minutes.
Stir in cilantro and reserved minced jalapeño with seeds to taste.
** Adapted from America's Test KitchenSpanish rice can be frozen for up to 3 months. Let it cool and then put it in an airtight container or heavy duty freezer bag to freeze.