Put the pepper quarters, skin side up, on the grill rack, brush with oil and grill for 10 minutes until the skins are blackened. Wrap in foil, leave to cool, then peel off the skins and roughly chop the flesh.
Lift the bread pan out of the machine and fit the blade. Put the ingredients in the pan, following the order specified for gluten-free breads in the manual. Add the chopped peppers and spring onions with the sugar and yeast.
Fit the pan into the machine and close the lid. Set to a 750 g (1½ lb) loaf size on a fast/rapid bake programme.
At the end of the programme lift the pan out of the machine and shake the bread out on to a wire rack. Brush the top with the butter and brown under the grill, if liked. Leave to cool.