Poach the chicken: Place the chicken breast in a small pot. Add the broth until just covered.
Sprinkle in the garlic powder, onion powder, and thyme. Bring to a gentle simmer over medium heat, then reduce to low. Cover and cook for 12–15 minutes, or until the chicken is cooked through and very tender.
Cook the veggies: While the chicken poaches, add the sweet potato and carrot to a second pot of boiling water.
Cook for 10–12 minutes, until very soft. Add peas in the last 2 minutes. Drain well.
Shred the chicken: Transfer the cooked chicken to a bowl.
Use two forks to shred it into very small, soft pieces. If needed, moisten with a few tablespoons of warm poaching liquid so it stays juicy.
Mash the base: Return the drained sweet potato, carrot, and peas to the pot. Add the butter and a splash of warm poaching liquid.
Mash until smooth or slightly chunky, depending on your child’s chewing skills. For younger toddlers, you can blend briefly with a splash more liquid to thin.
Combine gently: Stir the shredded chicken into the mash. Add yogurt (if using) and lemon juice.
Mix until creamy and cohesive. Taste and season with a tiny pinch of salt if desired.
Adjust texture: If it’s too thick, loosen with warm broth or water, 1 tablespoon at a time. The final texture should be soft and easy to scoop, not dry or sticky.
Cool and serve: Let it cool to lukewarm before serving.
Offer small, toddler-friendly portions and store the rest.