Prep ingredients: finely chop the onion and bell pepper, mince the garlic, drain and rinse the beans if using canned, and slice the avocado. Prepping everything before you start keeps cooking fast and prevents burning — chili development happens quickly once the meat hits the pan.

Heat a 10-inch skillet over medium-high heat and add 1 tablespoon olive oil. Allow the oil to shimmer but not smoke — this gives an even heat surface that helps properly brown the beef rather than steaming it.

Add the chopped onion and bell pepper to the hot oil and sauté 3–4 minutes until softened and the onion becomes translucent. Softening the vegetables first builds a sweet, aromatic base (the Maillard-like flavor from lightly browning the onion) that deepens the chili's overall flavor.

Stir in the minced garlic and cook 30 seconds, just until fragrant. Garlic burns quickly; adding it now prevents bitterness while still allowing it to bloom and flavor the oil.

Increase heat to medium-high and add the lean ground beef. Break it up with a wooden spoon into bite-sized pieces. Cook, without disturbing too much, for 3–4 minutes until the meat has mostly lost its pink and begins to brown in places. Browning develops savory, caramelized flavors that are essential to a restaurant-quality chili.

Season the beef with chili powder, ground cumin, smoked paprika, kosher salt, and black pepper. Stir and let the spices toast in the residual heat for 30–45 seconds — toasting spices helps release their essential oils and makes the spice profile brighter and more complex.

Add the canned diced tomatoes (with their juices) and the drained beans. Stir to combine and bring the mixture to a light simmer. The tomatoes provide acidity and body; simmering briefly concentrates flavors and melds the spices with the meat and beans.

Reduce heat to medium-low and simmer gently for 6–8 minutes, stirring occasionally, until the chili has thickened slightly and the flavors have married. Simmering allows liquid to reduce so the chili isn't soupy and lets the beans and meat absorb spice flavors.

Taste and adjust seasoning — add more salt, a pinch of sugar if the tomatoes taste too acidic, or an extra 1/4 teaspoon chili powder if you want more heat. Tasting at this point is critical; small adjustments elevate a home chili to restaurant quality.

Reheat the cooked brown rice if needed (microwave 30–45 seconds or warm on the stovetop with a splash of water). A warm bed of rice provides texture contrast and soaks up the chili's juices.

Assemble the bowl: spoon the brown rice into a shallow bowl, top with the beef & bean chili, and arrange sliced avocado on the side. Finish with a squeeze of lime and chopped cilantro if using. The cold, creamy avocado contrasts with the warm, spiced chili and brings a luxurious mouthfeel.

Serve immediately. Leftovers will keep in an airtight container in the refrigerator for up to 3 days — reheat gently on the stove or microwave, and add a splash of water if the chili has thickened too much.