A 10-month-old girl from urban Delhi presents with irritability, poor feeding, and generalized edema. On examination, she has pale conjunctivae, glossitis, and angular cheilitis. Hemoglobin is 8.2 g/dL with microcytic hypochromic indices. Serum albumin is 2.1 g/dL. The mother reports exclusive breastfeeding without any supplementary feeds or iron fortification. What is the most appropriate immediate next step in management?